The nominating ballot can be found here:
You do need to be a member to nominate. A member (attending or supporting) of LoneStarCon, this year's worldcon, or Chicon 8, the 2012 worldcon in Chicago, OR LonCon, the 2014 worldcon in London. Any one of the three will do.
All works first published or broadcast in 2012 are eligible.
The Hugo is the oldest award in our genre, the most prestigious, and the most important. It is a fan award. No juries. The readers choose the finalists, and the readers pick the winners. There will be five (sometimes six, in the event of a tie) nominees in each category.
I've said it before and I will say it again here: nominations are the most important part of the Hugo process. Hundreds of people cast Hugo ballots, but far fewer ever bother to nominate. You cannot win unless you are on the ballot, and sometimes the difference between being a finalist and an also-ran is a single nomination. Yes, even in the big categories, like Best Novel (last year one single vote was the difference between a novel that made the ballot and one that did not) and Best Dramatic Presentation. And in the less popular categories, hell, people have been known to make the Hugo ballot with twenty votes.
So NOMINATE. You have until March 10.
As to what you should nominate... well, that's your choice, of course. Right now, all over Ye Olde InterWeb, people are making their recommendations and writers are reminding the world about their own eligible works. I'll do the same, as I have in past years. But not in this post. Watch this space for my own favorites.