Hmm... Thats a tough one. I took the test at 5 PM. I just looked over some notes for about an hour then went out to eat. The remaining three hours I spent just bummin around on the internet and playing games and such. My main goal was to relax for a few hours before the test instead of cramming. That got my mind off the test for a while. I was definitely nervous going in, but once I got going it was done before I even knew what hit me.
Thats what I did, but everyone deals with stress differently, and doing stuff on the computer may not be your cup of tea, especially if you get headaches from being on them too long. I wouldn't want that to happen while I was testing.
I also made sure to get plenty of sleep the night before (easier said than done)