Russell T Davies has a penchant for using the names "Tyler", "Rose", "Delaney", "Donna", "Harkness" and "Jones" (most evident in "The Stolen Earth", which features four pre-existing Joneses). He likes to reference Ipswich. Ominous references to "the darkness" and "something is coming" abound. He often criticises religion and has a love of Humanist monologues ("Indomitable!"). He's prone to excessive use of Techno Babble in his Doctor Who stories, though for Who, this is no new thing.
Of course, some Doctor Who fans complain that RTD doesn't use enoughTechno Babble, claiming his sketchy explanations for whatever effect he wants to produce might as well be "A Wizard Did It". Major offenders include the "anti-plastic" in "Rose" and every Deus ex Machina season finale.
Fans often seem divided by his assumed "Gay Agenda", with everything from jokes from gay culture to same-sex kisses having found their way into his four Doctor Who series.
For an atheist, RTD won an award for irony when "Gridlock" (featuring renditions of "The Old Rugged Cross" and "Abide With Me") got nominated by a religious group for a prize for promoting Biblical values.
Although his work is noticeably stuffed full of religious imagery. Notable examples include "Last of the Time Lords" (the Doctor being rejuvenated by the entire populace of Earth praying for him, flying over the evil Master, then hugging him and saying "I forgive you.") and Torchwood's "End of Days" (essentially the same thing, with resurrected Jack forgiving the doubting Owen after... well, killing the Devil.) Davies' drama "The Second Coming" was nothing but religion, though of the kind that takes Nietzsche very literally...
And who could forget the moment in RTD's second ever episode of Doctor Who, "The End of the World", when we see the Earth burning away beneath a giant glowing space station ''in the shape of a crucifix''...◊
Another extremely apparent stylistic choice of his is phrase repetition. For example, "Hey, who turned out the lights?", "She is not complete", "Silence will fall", "Are you my mummy?", "Hello sweetie", "Spoilers", "Don't blink' - and that's just a few of the many, MANY Doctor Who examples, each repeated anywhere from about five to fifty times an episode. It's effective until you notice it, then it becomes a liver-destroying drinking game.
Moffat also seems to love sitcom-esque dialogue. His characters never miss a chance to be witty. Unless, of course, the joke is momentary awkwardness (see: any time Eleven says something dorky.)
He also includes children and childish/primal fears in his story lines.
A lot of the dialogue he writes, especially when it gets into the Techno Babble and Buffy Speak, tends to have a LOT of pauses and Motor Mouth moments. See: the Tenth Doctor and Tintin & Haddock in the film version of The Adventures Of Tin Tin (especially when Haddock is telling the story of the Unicorn).
"I tend to focus on one character (perhaps a young woman of unnatural abilities, to pull an example randomly out of nowhere) and then the other characters are built from the needs of that character's journey."
There's been a lot of comparison to the story of Echo being a sort of warped interpretation of the River Tam story, do you agree/disagree? — Vivienne
It wasn't meant that way, but I do have my little obsessions...
He's also fond of naming characters after things; just as a random sampling, Angel, Spike, Willow, Dawn, Faith, Glory, Harmony, Gunn, Jasmine, River, Wash, and Book.
Joss' middle name is Hill. And now you know.
Plus, the Actives in Dollhouse follow Theme Naming: Los Angeles uses the US military alphabet (e.g. Alpha, Echo, Victor, and Sierra), while DC uses Greek gods.
His penchant for snappy dialogue, snarkasm, and Buffy Speak is very distinctive. He did some Script Doctor work on the script of the first X-Men movie, but only two exchanges of dialogue made it to the final cut, and one of them has his fingerprints all over it:
Wolverine: Hey! It's me.
Cyclops: Prove it!
Wolverine: You're a dick.
Cyclops:[Shrugs, nods.] Okay.
The other, Storm's line about a toad getting hit by lightning, doesn't seem like his style; however, before his contributions were reduced, it was the deadpan climax to a highly Whedonesque Running Gag.
This style rubbed off on almost everyone who wrote for Trek over the years. Most notably Gene Roddenberry, Gene L Coon, and D.C. Fontana, but Michael Piller, Rick Berman, Branon Braga - all the big names got their shot at it.
During Star Trek: Voyager, if what you just saw involved Janeway being a) awesome and/or b) Ship Teased with Chakotay, usually both, it's more than likely Jeri Taylor's work. Brannon Braga, by contrast, actually lost his style as Trek progressed, since he began writing more and more of the series, culminating in Star Trek: Enterprise, where he and Rick Berman penned 37 of the 97 episodes; this meant that his normal Mind Screw could not be achieved week-to-week, and the two of them ended up with a shared Signature Style, which, alas, tended to focus on the crew of the NX-01 Enterprise bumbling around in space without any real idea what they were doing.
Terry Nation (Doctor Who, Blake's 7, The Survivors) liked doomed (and argumentative) groups of rebels fighting Scary Dogmatic Aliens like the Nazi-esque Daleks (which he invented) or in the case of B7, Scary Dogmatic Humans. He also liked ragtag (and argumentative) groups of survivors in After the End settings, and in "The Dalek Invasion of Earth", he even got to combine the two fascinations. He also had a great fondness for characters with the last name Tarrant and, often, characters with no first names ever given. A strong streak of cynicism runs through his work, making his favourite characters Deadpan Snarkers.
Look out also for his tendency to make up for his total aversion to Techno Babble by adding the word 'space' to existing nouns. Someone will be a doctor of 'space medicine'; an alien race's headquarters is referred to as being 'in Space' by space-travellers, and so on.
When Clark Johnson directs an episode in any given series, expect lots of handheld shots and shots of tangential, sometimes random but interesting events happening at the periphery of the scene. Called "Shoot the Dog" shots by the crew of the The Shield, after he excitedly insisted on filming nearby barking dog in one of the early episodes, different from the more familiar Shoot the Dog.
Aaron Sorkin, father of the Walk and Talk and Sorkin Relationship Moment: machine gun fast dialogue. Comedic repetition. Tall, smart, sexy, sassy women who give as good as they get. Characters who veer oh-so-close to cynicism, only to come back to hope and idealism. Extremely liberal world view. He actually included common criticisms of his writing style in his short play Hidden in this Picture. In it, a film director tells his Sorkin-proxy screenwriter, "I think your work has a tendency to be long-winded and cynical, I think you have trouble handling exposition, you take forever to introduce the inciting action, and all your female characters talk and act as if they've just stepped off the Love Boat."
Aaron Sorkin can be summed up by a quote from Margaret Mead: "Never doubt that a small group of thoughtful, committed citizens can change the world. Indeed, it is the only thing that ever has." Sorkin's characters are those people.
He also really, really likes to use the name Danny.
And the same character types. Watch The American President and The West Wing and then tell us A.J. MacInerney and Leo McGarry aren't the same character. Same with Lewis Rothschild and Josh Lyman, and that gets more fun when you add in Studio 60 and A Few Good Men, because Matt Albie and Dan Caffee are also the same character as Lewis and Josh.
He also likes to refer to offscreen characters multiple times by their full names before introducing them or explaining their purpose in the story.
And main characters often imply full sentences in arguments just by using the other character's first name.
Is the season finale named "What Kind of a Day Has It Been"? You're watching the first season of an Aaron Sorkin show.
His love of dramatic speeches. Is there a self-righteous villain in the piece? Then there will be a scene in which he delivers something not far short of a sermon, usually in response to hard questioning (in a legal setting), in which he concludes with a highly-quotable, exceptionally angry declaration which leaves everyone speechless.
Father issues. Nearly everybody on The West Wing has something rotten in their relationship with their father: Bartlet's father was a "Well Done, Son!" Guy who never actually said "well done son" and was physically abusive; Leo's father was an alcoholic who killed himself; Josh's father died suddenly the night they won the Illinois primary, contributing to his Guilt Complex; Toby has to forgive his father for being in the Jewish mafia; C.J.'s father is dying of Alzheimer's; Sam's father is revealed to have had an affair during his marriage that's lasted almost all of Sam's life. Charlie's father is the least talked about, and that's only because he was a Disappeared Dad; to make up for it, his mother was a police officer who was murdered, resulting in Charlie being Promoted To Parent at the age of twenty-one. In other works, we have, for instance, Danny in A Few Good Men trying to come to terms with his need to live up to his father's awesome reputation as a lawyer.
Sam's father's affair is an almost word-for-word retread of Jeremy's in Sports Night.
Sorkin uses the dialog construction "not for nothing, but ..." a great deal.
Bryan Fuller frequently gives his female leads boy's names, and his shows are very visually distinct, featuring sets, costuming and cinematography that make any shots from his work unmistakable in their origin. He frequently writes characters who are highly educated - perhaps overeducated - for their jobs, and disaffected by this fact. His characters often question their own mental stability, and to the audience the 'reality' of their perceptions will remain ambiguous. He likes to reuse actors and - perhaps the strongest sign a show is his - his premises involve weird, mildly disturbing relationships with food and/or death that are mined for macabre humor and heavy philosophical questions. For instance, resurrection with a price often features, as evidenced by his work on Dead Like Me, Pushing Daisies, and the Star Trek: Voyager episode "Mortal Coil". No one guessed he might create a TV series adaptation of Red Dragon until Hannibal - and yet once he did, the idea had a certain oddball perfection.
Jack Barry-Dan Enright: Generally solid quiz formats (unless they're trying to copy something else — for instance, Hollywood Connection was a blatant Match Game expy), extremely easy questions (likely over-compensation for the quiz show scandals of which they were a part in the 1950s), and a luck-based Bonus Round that involves some variant of "Find X amount of [good thing] before you find [bad thing]".
Bob Stewart: Word association games that are obviously trying to copy his huge hit, Pyramid. Often with super-cheap-looking but elaborate sets, and peppy themes by Bob Cobert. Bill Cullen is usually involved.
Reg Grundy: Proprietor of Australian adaptations of American game shows, always extremely faithful to what they copied.
Does the show you are watching take place in the past, focus primarily on women and their relationships with each other, handle what should be impossibly melodramatic storylines in a way that makes them, instead, utterly believable and heartbreaking, contain at least one romantic storyline which is restrained in expression yet incredibly profound, show the goodness of humanity in the midst of tragedy, and require everyone to Earn Their Happy Ending? Congratulations, you're watching something written by Heidi Thomas. See, for instance, Lilies, Ballet Shoes, Cranford, the Upstairs Downstairs revival, and Call the Midwife.
Toshiki Inoue, a prominent Tokusatsu writer known for his work on Kamen Rider, is really known for his use of the Conflict Ball and Poor Communication Kills. Sometimes, the plot of the show could be solved if the characters would just sit down and talk to each other for just a few minutes, but due to often contrived circumstances, they just keep fighting one and another. Also, if there is a romance in the show, you can count on it that the female involved in the romance will die to give the male character motivation to fight the villains.
Yasuko Kobayashi, known for writing multiple Kamen Rider and Super Sentai series, has a very unique style of writing. She almost never plays tropes straight, depends on Show, Don't Tell and does not shy away from introducing new tropes to the Tokusatsu genre. T Vtropes even has an analysis on her signature style, which can be found here.