Hmm, well, I'm not really sure. I usually just find one I like and join up. I'm not very good with coming up with the ideas myself. I certainly prefer hetero, though after that I get a little varied. I've done anything from romantic to rape, which is why I usually just let others choose the story for me and then just conform to that.
Unfortunately, I tend to like rather rare or not as often-done stories, usually non-modern, like Roman, Trojan or Greek, (be it mortals or Gods), Tribal, Renaissance, or medieval (especially King Arthur era.) As a result, I don't roleplay as much as I'd like because I can't find roleplays that suit my preferred style. This site seemed to have a good variety though, so maybe I'll find some luck here and find the sort of rp I'm after.