Is your test center your local university? If so, avoid the long waiting line that situates everyone into the various test rooms and get in the line last. Once you're seated, depending on who is in the room with you, it could be extremely distracting. I had a girl sitting in front of me that was constantly tapping her shoe and my friend had someone coughing in her room. It was agonizing in the beginning, but you have to zone it out. Also, make sure you're well hydrated, properly nourished, and bladder well maintained. Even if you don't feel like you have to pee before the test, pee anyways! Other than that, I think the only other thing that I personally experienced that was different from simulated test-day conditions is time. I felt as if 35 minutes FLEW by and this could have honestly been nerves/adrenaline.