Science fiction brings to mind lots of stock images, from androids to spaceships, first contact with aliens and machines that let us travel through time. It's a vast and multilayered genre on par with Fantasy (which is why the two genres are often paired together in the acronym "SF&F"). But how do you tell a good science fiction story?
We'd be amiss if we didn't first recommend checking out So You Want To Write A Story for advice on how to tell a good story above all else. Also, check out the Speculative Fiction index: it's the supertrope of Science-Fiction, and contains many, many tropes that are applicable to this genre.
First, you need science. Seems self-explanatory, but it's much, much trickier than you think. Science in fiction can range from hard to soft, from accurately researched and plausible (like basing your spaceship off real-world NASA rockets) to Technobabble and Applied Phlebotinum to Hand-Waved plot devices. Most audiences only have a very basic grasp of scientific principles (if even that much), but there is such a thing as Willing Suspension of Disbelief. The key is to make the rules of your fictional world consistent, whether it's based on Real Life or your own imagination.
Second, you need to address which scientific issue is at the root of your story. Most people think of outer space and aliens when they hear science fiction, but that's just the tip of the iceberg. Some stories are about Time Travel, others are about Genetic Engineering, and still others are about how A.I. Is a Crapshoot. The first arguable work of science fiction was Mary Shelley's Frankenstein, which is about the ethics and trauma of Creating Life. Once you've got a grasp on what kind of science you're dealing with, you can work out the kind of story you'd like to tell based on that premise.
Isaac Asimov published an article in 1953 entitled "Social Science Fiction." In it, he posited that all SF falls into one of three categories, obligingly catalogued on This Very Wiki as Asimov's Three Kinds of Science Fiction:
- Gadget-based SF is about the invention of a new technology. These days, Technobabble may result, but back in Asimov's day you were expected to actually know something about science, so many of those ideas were scientifically valid. ("I want to create a very small television-creating device! It can record moving pictures but be the size of a button! I want to create... the hidden camera!")
- Adventure-based SF is about how the new technology can be used—Applied Phlebotinum, in other words. It typically causes the plot, but rarely as a MacGuffin because its properties will then have bearing on resolving it. ("Help, help! Now that I've invented the hidden camera, unsavory types have kidnapped my Beautiful Daughter! She's being held in a dungeon that can only be plumbed if someone takes my brand-new hidden camera with them!")
- Social SF is when Reality Ensues and Misapplied Phlebotinum rears its ugly head. The new technology is widespread, the beautiful daughter is safe and sound... but what's going to happen to the world now that we can have tiny cameras everywhere? What if we were to take photos of people in compromising positions and use them against that person? What if we were to imprison a man within The Masquerade and broadcast his bumbling misadventures for our own entertainment? How are we going to solve the new problems created by the new technology? Adventure-SF is about how it can be used, but Social-SF is about how it should be used.
Most science-fiction these days involves pieces of all three, though the latter two are by far the most predominant. In fact, the two of them together—what the technology is/was, and how it is/was used—have given rise to a whole mess of subgenres within the science-fiction proper. The Other Wiki has the following list (though with a "Citation Needed" tag, so feel free to add or elaborate as you desire):
- Cyberpunk: a dystopian future where information technology has allowed corporations to subvert the government. The almighty dollar rules all, Might Makes Right, and the protagonist is typically an oppressed commoner who still, somehow, has the skills and guts to make a change in the world (though not always a good one).
- Military Science-Fiction: Military fiction Recycled In Space. Typically focusing on a soldier and The Squad around him, it explores what war might be like in the future. Expect a lot of gadgets, War Is Hell, and maybe a Ray Gun or two (though, in a more realistic setting, weapons that don't shoot very bright, very shiny beams of light may be preferred).
- Superhuman: this genre concerns the emergence of the Transhuman and what that means for the rest of us muggles. All of the Other Reindeer is the most Necessary Weasel here, since said transhuman will probably experience prejudice and feel annoyed by it.
- Apocalyptic and Post-Apocalyptic: fiction set After the End. The Apocalypse How can vary—disease, war, ecological disaster, astronomic impact, zombie plague—transhumans run amok—but this brand of fiction typically involves itself with Action Survivors struggling to rebuild, or at least survive, as everything comes crashing down around their ears.
- Space Opera: drama, or even melodrama, on a galactic scale. It typically takes place in a well-developed and well-populated universe (though the presence of aliens, Rubber Forehead or Starfish, is optional) and at least one interstellar nation, against which is pitted an opponent who can match it blow for blow. Originally a derogatory name (a snowclone of Soap Opera), it has lost its pejorative connotations—The Empire Strikes Back was something of a turning point for it.
- Space Western: the Western, Recycled In Space! While post-apocalyptic fiction takes place After the End, this genre happens Before The Beginning. You know those space empires we just talked about, that are having their war in a Space Opera? How did they begin? What was Settling the Frontier like on this planet, or any other? This genre answers that question by having a wagon train Walking the Earth. ...in space.
- Time Travel: typically, this involves someone going into the past and screwing things up somehow, creating an Alternate History, or at least having a wonderland adventure exploring the world of yesterday. It can be difficult to write well due to logical paradoxes resulting, as well as the fact that—according to Albert Einstein at least—time travel is physically impossible.
Finally, you should address the Mohs Scale of Science Fiction Hardness, a (tongue-in-cheek) assessment of scientific accuracy. One of the defining aspects of science-fiction is that it contains Phlebotinum—some sort of new gadget that does stuff which was formerly impossible. The Mohs Scale asks, "What rules govern your Phlebotinum, and are you sticking to Internal Consistency regarding those rules?" Scientific validity is nice too, but is often glossed over because of just how much research is necessary to achieve it; plus, Science Marches On, meaning that even if your story is accurate today, someone might prove it wrong tomorrow. Fortunately, the Mohs Scale doesn't ding you for that.
Let's say you have a Subspace Ansible, allowing faster-than-light communication. According to Einstein, ain't nothing moves faster than light—this is an immutable law of physics. So the existence of a Subspace Ansible automatically lowers your story's position on the Mohs Scale, because you are violating the laws of physics. However, we then get into the question of how the ansible works. What (plot) device are you using to violate the laws of physics? Well, if you invent some Technobabble about localized artificial wormholes and such that let you pass physical objects through—say, electromagnetic radiation—you go even lower on the scale, in addition to Digging Yourself Deeper in terms of explaining how those are created. But if you do some research, you can find out about quantum entanglement, a subatomic form of Twin Telepathy that may allow genuine FTL communication to exist in the future. This boosts you up the scale a little bit because at least you have a semi-scientific leg to stand on.
But then let's say your characters invent a new gadget that lets them send massive energy pulses through the ansible, to the point that you can cause the receiving ansible to explode and kill the person operating it. Ansibles are now weapons. How are you going to explain that? At current time, there is no known way of sending energy down a quantum-entanglement link (indeed, there is no known way of manipulating the entangled particles without de-entangling them, thus limiting the currently understood applications of the phenomenon), and if your characters do this, you'll get dinged on the Mohs Scale. Conversely, that localized-artificial-wormholes crap suddenly looks much more plausible, since—while said phenomenon is not necessarily scientifically valid—you already established that physical objects can be transmitted through the ansible. The ability to supercharge one like a bomb no longer looks like an Ass Pull; indeed, it's consistent with the (artificial) laws you created earlier, and thus your Mohs rating goes up.
The lesson to be learned here is that Internal Consistency matters in science-fiction. If [Thing] is not supposed to happen, it should not happen, and if it does you had better be building up to it. For instance, by creating a gadget that lets you do it. Or, to put it another way, Don't create rules you don't plan to follow.
The "Science" Part
One of the most obvious pitfalls you'll need to address is, well, science. As Science Marches On, it becomes harder and harder to tell stories that speculate on what could be true, because we already know what is true. There was once a day when you could tell a story about the moon being made of cheese and be taken seriously, because there was simply no evidence for or against. But needless to say, that day has passed.
This has two implications for you. The first one is that you'll have to dig deeper, do a lot more research, before you can find any science to speculate on. There are many, many areas where knowledge is still lacking (cognitive science and neurology; particle physics; genetic engineering), but much of the low-hanging fruit has already been plucked, both by writers and scientists. The second is that once you find the science you're going to harp on, explaining it to the audience may be a lot harder. "E = mc2" is relatively easy to grasp. Quantum Physics, which descended from it, is not.
Note, though, that there's a lot of research to be done. If possible, stick to current conventions and ideas. For instance, most atomic elements have names that end in "-ium" (potassium, einsteinium, californium; "aluminum" is a weird corner-case, especially since it is known as "aluminium" in every other country besides America). Adding on a completely different suffix ("alamantarite"?) would raise protest from most Real World scientists, and thus probably would in your fictional universe too. (Unless you have a "Just So" Story to justify it; and, of course, you are allowed to craft one.) Another example is species names. In most science-fiction (and fantasy too!), species names are capitalized as though they are proper titles: Klingons from Star Trek, Daleks from Doctor Who, Wookiees from Star Wars, Cylons in Battlestar Galactica, Minbari in Babylon 5, etc. This is not how species names are handled terrestrially; when you are referring to your pet Dog, you don't— see?? Nor do we talk about Oak Trees or Salmon or Blue-Footed Boobies. All of these things are lowercase, the same way "human" is. And yet the "capitalized species name" trope is so ingrained in most viewers that they will react with confusion if they see lowercase ones. Even though, according to modern scientific practice, they all should have been lowercase from the start.
The "Fiction" Part
Technology drives a science-fiction story, but a science-fiction story doesn't have to be about technology. That's one of the key distinctions Asimov made by pointing out that Social Science Fiction exists. The problem is that SF caters these days to people in both camps—the ones who like Adventure stories and the ones who like Social stories.
Adventure stories are, well, adventure stories. There's a clear three-act structure: inventor creates Phlebotinum; Phlebotinum goes awry; inventor needs to solve the problem. Done well, these stories have a lot to say about people, the human condition, and the dangers of technology; done poorly, and they're basically Action Movies with lasers instead of bullets, spaceships instead of cars. By definition, these stories need to be gadget-driven, since without them it is just an Action Movie, and so lots of time is sunk into the Green Rocks that sprout New Powers as the Plot Demands, as mandated by the Rule of Cool. Again, Willing Suspension of Disbelief can take a major hit here, especially if you're dealing with a "literary" critic used to reading "real" fiction.
Social stories take the opposite tack. The gadgets are downplayed... except for their impact on the protagonist and/or the world; that impact is the story. (So in this case, incidentally, the gadget can be a MacGuffin, though it typically isn't.) Done well, these stories have a lot to say about people, the human condition, and the dangers of technology; done poorly, they can come across as preachy, Anvilicious Author Tracts. By definition, these stories need to be preachy, since they posit the effects of technology on society, but it takes a subtle hand to do this well; human nature is something that everyone is familiar with, and if you breach it, you break Willing Suspension of Disbelief.
Throw all this together and you start understanding why the Sci Fi Ghetto exists, why Sturgeon's Law ("90% of everything is crap") was first formulated in response to someone remarking that 90% of sci-fi was crap, why an entire pejorative label—the mispronunciation of Sci-Fi as "skiffy"—has been created for crap stories.
Of course, you don't have to just pick your poison. You can have rollicking good action and social commentary in a commercially-acceptable package. The X-Men are just one example: the technology is mutation, and the franchise has spent its share of time dealing with mutant-Muggle tensions (Fantastic Racism, Have You Tried Not Being a Monster?) alongside the typical exploits of a superhero team (The Dark Phoenix Saga, Days of Future Past, etc). It's done a pretty good job with both of them. The reason science-fiction endures as a genre is because it can be done right.
So how do we do it right? Simple.
The antidote for excessive gadgetry is Character Development. A swiss-army gadget might be cool in its own right, but it's much more memorable when wielded by an in interesting character. Additionally, if you start messing around with the character, you'll start losing focus on the gadget—partially because the character's probably more interesting, and partially because the character can do things the gadget itself used to do ("I need this Ray Gun to be able to speak French! How do I realistically... Oh, right, Bob can speak it!"). If James Bond didn't have a personality, he wouldn't be famous for all the marvellous toys Q Branch provides him. In fact, he wouldn't be famous at all. In X-Men's case, it's more about the powers, and there are characters who definitely demonstrate this. Cyclops is one example: he's The Hero, an upstanding boyscout who can level mountains with laser beams shot from his eyes... and has always been the bottom of the heap in terms of popularity, because he's just not that compelling. In comparison, you have someone like Gambit, whose power is comparatively stupid—he throws exploding playing cards, for chrissakes—but comes with a cool-enough personality that he's going to be played by Channing Tatum. It is, in other words, possible for a story to have gadgets but still be about people, and that's the angle you should aim for.
And the antidote for preachiness is, well, non-preachiness. You should ask the hard questions: How could this be abused? Where could things go Off the Rails? We can do this, but should we? But you don't have to answer them. Let various characters react in various ways, and don't pass judgment. Make sure Both Sides Have a Point, and let both sides live with their points. Once again, the X-Men—specifically, X-Men: The Last Stand—provides an instructive demonstration. One of its plot points is that someone has come up with a "cure" for mutancy, a permanent Power Nullifier that turns you back into a muggle. Most mutants reject it, but one—Rogue, played by Anna Paquin—decides to go for it. Her personality in a nutshell is, "I Just Want to Be Loved," but her mutant power is a Power Parasite / Touch of Death combo, and she has permanent Power Incontinence. As a result, she Can't Have Sex, Ever, or even touch people for longer than about five seconds. So she decides to depower herself, despite the protests of other characters, and for the remainder of the trilogy (all five minutes of it remaining, by that point) she has to live with it. And, most importantly, the movie doesn't try to hang An Aesop on it by saying, "She was right," or "She was wrong." The movie just shows her doing it and lets the audience decide that for themselves. It is, in other words, possible to be thought-provoking without being anvilicious, and that's the angle you should aim for.
One of the core tenets of science-fiction is that it typically takes place in the future. This is because it typically involves the existence of technology we don't have yet. There are some exceptions—Star Wars famously takes place A Long Time Ago, in a Galaxy Far Far Away...—but very few. (And even so, Star Wars is really more of a Science Fantasy than anything else—at least, according to Word of God. Of course, that God also gave us midi-chlorians, so you'd be forgiven for taking anything he says with a grain of salt.) Might it be possible to create a sci-fi story that takes place in the past? There is a genre of fiction called Alternate History which arguably counts, but those typically involve Alternate Timelines where something very specifically went differently than it did in the history of our world (IE Nazis won D-Day; the North lost The American Civil War; dragons exist). Might it be possible to write an historical science-fiction story that takes place in our universe?, in the timeline you and I live in? Spy fiction is arguably the place this happens most; James Bond is constantly dealing with (and occasionally slinging around himself) gadgets and tech that don't exist in our world and were created by the villain. In a similar vein, the Metal Gear video games take place in a world that, at least at first, is identical to our own; as time went on, it diverged further and further so that Hideo Kojima could better present his various Author Tracts.
One of the core tenets of science-fiction is that it typically involves the invention of new technology. Well, that's not always necessary; there's a lot of old technology lying around that might do the job you're looking for. This is part of how the Space Western justifies its tone. "Sure, I could use a hovercar to cross the continent, but doing so is dangerous because the technology is unreliable" (note that Space Westerns almost always take place in a Used Future) "and if it breaks down, I'm stuck in the middle of nowhere—on a planet that's barely settled!—and may possibly lack any ability to fix the darn thing. Compare this to horses, which are lower-tech but much more reliable. Which option should I pick, and why? And what new problems will it cause—or rather, what old problems will be brought back?" Science-fiction is typically about using new technology to solve old problems; but what about using old tech to solve new ones?
Whenever possible, use Minovsky Physics. The trope namer is Mobile Suit Gundam, a Real Robot genre that makes use of Humongous Mecha. Now, Humongous Mecha are Awesome, but Impractical in real life—so impractical that they'll probably never exist. So how do you write a realistic series involving them? Simple: Minovsky Physics, which are a set of new physical conditions or rules that justify the story you want to make. As an example, Frank Herbert wanted Dune to have Archaic Weapons For An Advanced Age; he wanted his characters to have Sword Fights, even though the story takes place in something like 23,000 AD, and swords have been obsolete ever since guns became practical in the 1500s, meaning there was no intelligent reason for edged weapons to be used, in earnest, during military maneuvers. Herbert's Minovsky Physics were personal Deflector Shields—pretty scientifically accurate ones too. If you're going to wear a personal shield that keeps everything out to the subatomic level, well... how're you gonna breathe? The thing's blocking all oxygen circulation. So deflector shields in the "Duniverse" stop things that are only going above a certain velocity, like bullets or collimated photons (IE Frickin' Laser Beams); slow stuff—say, oxygen molecules, or carbon dioxide—can get through. That also means that the best way to kill someone while his shield is up? Is to Back Stab him, slowly. Boom: justification for using swords. "Because I Want To Write The Story That Way" is never a sufficient reason. Back-engineer the physics and science of the story to make your desires seem, not only clever, but inevitable.
This also gets back to something referenced above: human nature. The Rule of Cool works in fiction, but it does not work in Real Life. It may be awesome to think of your technologically-advanced crusaders using longswords against foes armed with pinpoint-accurate laser weapons and wearing armor strong enough to deflect directed explosives, but if you want to maintain Willing Suspension of Disbelief you have to justify it. Why would anyone use a length of sharpened metal against someone who can kill you from a mile away?—and, assuming you somehow manage to get close enough to stab them, whom you have to hit in juuuust the right spot to have any hope of actually hurting? This is a bad idea. And if you want your characters to do it anyway, you—the author—have to come up with some intelligent justification. Otherwise The Reader will assume your hero characters are Too Stupid To Live. And The Reader is always right.
Suggested Themes, Plots, and Aesops
Technology: the awesome things it can do, the bad things it can do. We've been over the suggested plots, and the (possible) value of avoiding aesops.
Set Designer / Location Scout
Just about anywhere, when you get down to it. Most science-fiction is, as mentioned, set in the future, but this can vary from Crystal Spires and Togas to Used Future. It also depends on the exact when you decide to deal with; Twenty Minutes In The Future versus gazillions of years (such Dune, which takes place in the year 10,191 of its own Alternative Calendar). So you should figure out the tone of your when.
There is a huge variety in the props you can use, given the (again) wide variety of settings. Star Trek, set in the 23rd century, has omnipresent Frickin' Laser Beams, Teleporters and Transporters, Deflector Shields on their Cool Spaceships, Translator Microbes, Antimatter, and more; Halo, set in the 26th, holds that Kinetic Weapons Are Just Better and arms its Space Marines with gunpowder-based weapons. Of course, it also has a Player Character with Powered Armor containing a fusion reactor, an onboard Artificial Intelligence and personal Deflector Shields, which are all things Star Trek has never (canonically) exhibited, so you could have all sorts of Fan Wank about which franchise has an edge in advanced technology.
There are two decisions you need to make: what your central characters' technology level is and what your average technology level is. This is especially important since your main characters will probably live at a higher tech level than the world at large. The characters of Star Trek live on a Cool Spaceship, but we don't spend nearly as much time on the average rank-and-file of The Federation. What's it like if you're just a normal citizen living on Earth, or Vulcan, or Betazed? When you're just living in your house, do you have easy access to a transporter? To holodecks? To replicators? To Casual Interstellar Travel? To photon torpedoes? And if you're going to write a story about multiple cultures (Space Opera, Space Western, Transhuman, etc), you'll need to specify the technology level of those cultures too. Going back to Halo, we have not only the tech level the UNSC lives at (rifles that fire bullets) and the tech level that the SPARTAN-II Player Character and his friends live at: there's also the enemy, a consortium of aliens called "The Covenant" who are united by their worship of the Forerunners, the franchise's Precursors. They also have access to a bunch of Forerunner-based technology, which are incredibly powerful despite the fact that the Covenant don't quite understand how even their own inferior knockoffs actually work. So they too have personal Deflector Shields (two kinds!—the ones on the Elites and Brutes, and then the big oval forearm shields of the Jackals), Invisibility Cloaks, Plasma and Energy Weapons, Laser Blades and more. (A lot more: it's canon that naval engagements are almost always Curb Stomp Battles in the Covenant's favor, because their Forerunner-influenced ships are Game-Breaker powerful.)
Note, additionally, that your main characters' tech level does not have to be higher than that of The 'Verse, it just has to be different. In Firefly there are laser pistols and Energy Weapons on their Cool Starships and advanced medical technologies and treatments that can make people telepathic... and we only kind of see the edges of this, because we're largely hanging out with a Ragtag Bunch of Misfits on a broke-down Firefly-class transport that doesn't even have guns on it. Of course, it reflects well on our main characters that they are able to get along with pluck, creativity and a minimum of Applied Phlebotinum. Plus, Firefly is a Space Western, and specifically takes place on the less-civilized fringes of the solar system because The Captain doesn't want to have anything to do with the sprawling, bloated bureaucracy of the Alliance. But the point is, if your characters exist on a distinct tech level, whether it is higher or lower than the average, they are more distinct and memorable.
Physics. Actual physics, preferably, as opposed to things like Space Is an Ocean or Faster-Than-Light Travel (another thing that is, at the moment, believed physically impossible). Of course, viewers might not have any idea what consists of realistic physics; you can also run into Reality Is Unrealistic if you do go for realism. (There's a tale, possibly apocryphal, about someone who went to a test screening of Apollo 13 and left the theatre scoffing, "I don't like the tacked-on happy ending. If this had really happened, there's no way the astronauts would've made it home.")
Dune is the Lord of the Rings of science-fiction. It's written in luxuriant prose, has the kind of explosive Back Story Tolkien indulged in, and for a bonus was the Trope Codifier for working Green Aesops into the genre. It completely changed the public conception of what science-fiction was capable of.
For television, check out Star Trek, a Long Runner that has a great deal of quality work behind them (though, as with everything, some not-so-quality as well). The show operates from a position that Some Anvils Need to Be Dropped, though as a consequence it has built up a reputation for being Anvilicious (see Let That Be Your Last Battlefield for an example). It also took place in a World Half Full and was known for taking for granted several social advances that still haven't come to pass yet (specifically, the idea that people of different races can work together without anyone making derogatory comments).
And that's just to start with. For other inspiring examples, check out works that have won the Hugo Award, Nebula Award and Seiun Award, the three most prestigious (roughly in that order) accolades that a science-fiction work can win.