Recopying from another post I made...
I don't know. It gets really bad when stuff you think is funny no one else does. Or when half the people think you're hilarious, and the other half just wonders why you're talking like that.
Point is, comedy is frikking odd.
But, there are joke theories to study and learn.
For example, you already have "witty" dialogue, which many people find to be a form of comedy (Buffy the vampire slayer).
A form of comedy I HATE but some love (like Cakman), is "awkward" humor (Curb your Enthusiasm, Tim and Eric). This is humor that comes from awkwardness of situations, and often has no real punchline, or when it does, it's a slow creep, it's not a stated BAM.
k. Similar to quirky humor, but fundamentally different. Quirky humor is usually something that is running,
One that I use a lot, (although I apparently suck at it) is "quirky" humor (One Piece, One Piece, ONE PIECE!). You know this humor. A guy has a mushroom on his head. Why? Never commented on in story. IT JUST IS.
You have slapstick (The Simpsons) which is usually considered LCD, but when done well, can be quite amusing.
Absurdist humor, which is your typical Monty Python flic-
CAKMAN, SIGNIFICANT OTHER TO AHR HERE.
I would disagree in the notion just stated, and say that, in fact, Tim and Eric would also count as absurdist humor.
But to answer you straight, when it comes to being funny, getting people to laugh is not difficult at all. The easy way to do it is to do it through small things- easy to make puns or wordplay. Take the topic at hand, figure out a way to hamfist a pun into it.
The thing you want to avoid the most is two things:
"Random" humor, which is frequently attempted, rarely succeed. Saying a word or a phrase that you find to be funny to simply shout out at an unoppertune time will never be funny. It doesn't matter how hilarious you find the word "muffin" to be; if you shout that out, it's not going to garner a laugh.
The other thing would be "references." A personal experience with this: When I was in high school, in health class, I sat in front of a guy who would do a Glen Quagmire impression and say "Giggity"every time the teacher said something related to sex. If he is dead tomorrow, it won't be soon enough. Even if you find a show or book or comedien funny, if you reference them, make sure it is done in the purely referiential sense- you simply saying "Yeah, it's like that old George Carlin bit..."
Which, now that I mention it, is another way to improve your sense of humor. Listen to some stand-up comedey. Specifically, look at George Carlin, Jim Gaffigan, for some dirtyish stuff, Mitch Hedberg, Steven Wright for some intermediete stuff, and Brian Regan or maybe even Bill Cosby for clean material. Listen to some of their acts- Try looking up Carlin's "You're All Diseased"album or Bill Cosby's "Revenge" album. Listen to them, and think about what makes you laugh, and WHY you're laughing. What was it that the person did that caused you to respond in that way?
Once you have this down, it's a matter of merely coming up with witty observations at the appropriate times. It sounds a bit obtuse, but that's really the best advice I can give you. But seriously- look those guys up. Try listening to them.
-k, which is slightly different then than quirky humor, in that it might have a punchline, it just doesn't always make complete sense.
Finally, Voice Humor, which is something that only works in media with vocals. Lines that are made funny because of its delivery. Easy to write, but hard to pull off, since you need someone with talent.
Anywho, that's some basic easy to follow methods of humor, have fun!