I've found, after going through a couple of serious fandoms now, that I go through three stages: 1) New to it, write my own take on the show (often using what I later discover are cliches, but what I think are Totally Original), 2) After obsessively immersing myself in everyone else's fanfic, writing stuff that mirrors the take I like on the show/film/whatever, and 3) Finally finding how I like to write the fandom.

And then I run out of ideas. *g*