I just blocked everything out. Seriously, it sounds like it's not that helpful but I've noticed a lot of my anxiety arose when I paid too much attention to my surroundings (other people bragging, noises in the room, etc.) instead of the test in front of me. I knew that I could do well but I get affected (pissed off) by braggarts and tend to dwell on that instead of concentrating on my test. I brought my ipod and a book to read during lunch so I wouldn't have to listen to other people. In my test center we sat next to the person we stood next to while waiting to be registered. I was lucky.I knew the lady next to me (she worked upstairs) and she was really down to earth and I could joke with her during breaks and that definitely helped. So, watch for someone you know who is friendly, it will definitely help.
If you get tripped up by a question that's ok. The questions are hard! They are trying to trip you up. Everyone else is having trouble with it, too. Be confident in yourself. Attitude goes a long way. Take a deep breath, skip the question, and remember to return to it later. You'll do fine.