The Homebrew Con website has some pretty good tips. Mostly you want to make sure to carry a glass around with you (Use the sample glass they give you and keep in in your lanyard!) because there is beer to try EVERYWHERE.
And remember that it's a marathon, not a sprint (Except for certain bus tours and Club Night...)
Take small samples and drink plenty of water too.
Check the area that showcases equipment, etc. They have SCHWAG to give out, contests, etc. Lots of neat stuff to look at.
You will get a care package with your pass, SCHWAG, glass, schedule, etc. when you arrive and check into the convention. You might get commemorative beers from local brewery(s).
Wear a Homebrewtalk sticker or something and see if you can find other HBT members.
There are lots of homebrew "Celebrities" attending, usually, like Palmer, Strong, Mosher, Papazian, etc. If you've ever wanted to ask them a question, or thank them in person, it's a great opportunity for that.