FWIW, humor's not that difficult to figure out, it's all about having a unique perspective on stuff and exaggerating reality.
That being said, there's different kinds of humor, some of which are not good with women. Examples:
Someone says, 'you got a lot of body hair!, and you come back with, 'yeah, I like to rub sugar in it and catch flies that way' - while maybe funny, it's also self-deprecating, e.g. BAD
Or a joke like, 'What's that fleshy stuff around the vagina called? A woman' - while funny to guys, probably less so to most girls, e.g. BAD
Too goofy is also bad.
BUT!
Let's say the girl attends college and you've got a job; after talking to her, you can say something like, 'now back to studying for you, you gotta finish college cuz I'm looking for someone to support me'
Or let's say she's got an exam coming up. You can tell her 'no pressure with the exams; if you drop out of college, they're looking for a cleaning lady at my company. You get a decent salary plus benefits'
She giggles and says, 'what benefits?', to which you can say, 'you get your own mop, dustcloth and bucket, pluds the added benefit of being around me'
Now for example, in my country (and in much of Europe) there's this day called 'Fat Thursday' where you basically eat a ****load of donuts. I send a quick text, 'easy on the donuts today, allright?'
Another one, which only works when you've got the girl's number and she's got your number and knows who you are. You call her up and say something completely random like 'Hello? Is this the National Deaf-Mute Association? I'd like to sign up if at all possible'.
Generally, you can watch some stand-up some stand-up comedians, or even better, go watch all Evenings with Kevin Smith. The guy's hilarious, but you gotta be careful, because he's got a lot of self-deprecating stuff, but HE can get away with it because he's got money/status.
A good example of the 'self-deprecating humor is not good with women' theory is Cona O'Brien. Conan is popular as **** with guys, and I personally nearly die laughing from some of his stuff, but he's ALL about self-deprecating, and women don't respond as well as guys to him, or at least that has been my experience.
