When you make up fanfic, is there any particular quirk/technique you have for picturing scenes? For example, I have a big playlist of dramatic or otherwise evocative music, usually but not always from movie/anime/game OSTs, that I essentially choreograph to. Not that I've managed to commit any of it to the written word since I end up thinking of like three+ AUs to any given fic idea and get indecisive.

Alternately (if the answer's "it just comes to me" or whatever), is there any fandom you've gotten into completely due to having read good crossover fic with a fandom you are already familiar with?