What I do is I take the list of eligible fics and start reading. Each fic gets a 1-4 rating (with in-between ones like 2-3 and 3-4). I write a description of the story and put it with title and rating under the appropriate categories. I do *not* write the author there. That helps me not focus on authors so much, just the stories that stuck out based on good description, dialogue, plot, etc. I only nominate 3-4 and 4 rating stories, 4s being the ones I read that left me slightly breathless and stunned. There's always a few every year, and at least half of 'em nearly always win in some category or another, often best overall. Only time I do pay attention to authors is in deciding who to vote for, I try to make sure I haven't voted on a particular story or author for too many categories, unless the stories just plain stand above the rest. When it's impossibly close, though, I figure it makes more sense to spread it out.
So that's how I do it . . . though I'm really behind. Right now I'm still going through new author fics, much less the rest of the list! I'll be up late a few nights trying to get 'em read, evaluated, and noms sent in in time, I'm sure . . .
