...Or how did your genre choose you (courtesy of Michelle).
I don't think about it so much until after. Because if I told myself, "I want to write something contemporary," no contemporary ideas will come to me. If there were any simmering, they will hibernate. I know, because I've tried it before.
I thought, "I'd like to write a good urban fantasy minus supernatural creatures." Nothing came. Then I forgot about it, and, what do you know, my latest WIP is urban fantasy, and has no supernatural creatures.
When I wrote Unthawed, I really had no idea what it was. I still have no idea what it is, really. Thank you speculative fiction for giving me a nice, sweeping genre to put this thing in. It's definitely some sort of sci-fi, and it could probably be called post-apocalyptic, but both of those just feel so misleading.
I could never have anticipated something that started with, "I want to write a story with mammoths in it" would become what it did. And I'm glad I didn't try to label it before I wrote it, because I think I would only have confused myself.
I think generally speaking, science fiction and fantasy call to me more. Fantasy, in particular, is my brain's snuggly place. So most of my ideas are going to land somewhere around there. But look out, other genres. I will come for you one day.
Visit YA Highway for other posts on this topic, and to link your own!