<gingerly stepping between combatants raising flame-throwers just before triggers are pulled back full....>
Oscar---there are so many different types of humor that you may have a few already and not recognize it.
For example, I read D'Angeles' or D'Angelos' (I forget the name) examples of C&F and find about 20% or 25% funny. I figure the rest of it has to be in the moment and delivered in a certain tone that I'm just not picking up from the newsletter.
Or I have quite a bit different type of humor than he does.
I use sarcasm. I point out contradictions. I have a certain feel for the absurd (shared by few, unfortunately...) I dearly love word-play and will admit to occasionally engaging in a pun, but I truly deeply madly love playing with ideas (a level beyond wordplay) in such fashion that ideas become juxtaposed or pun-like (sorry, can't provide examples, it's all contextual...)
And I use it as MY test of those around me. If you unaware I told a joke, you have no chance of anything beyond a ONS and even that is questionable. If you get the humor, you've got my attention. And if you can reply or play with it, ah.....!
Find your humor out of yourself (what makes you laugh, what you find funny in life, etc.) and grow out of that. Imatating others will get you started---to a point. This would be trying things for fit, so to speak, but should be quickly worked thru or you become annoying and imatative (both traits are social killers..)
And if you find you have no sense of humor (you can't laugh, you never laugh, or--like someone tone-deaf, you just can't convey humor of any sort regardless of what you try) then rely on some other trait and take her to comedy clubs.