Answer:
Drink plenty of water, stay calm and don't focus or fixate about your surroundings so much, they can distract you too much. Don't freak out if you don't know an answer, you can probably flag it down for later if the system allows that. Wear VERY comfy clothing because if you get discomfort from a random piece of clothing, it's going to bother you the entire exam. Get plenty of rest, and have a healthy breakfast/meal/snack prior to the session. Bring along a book if you can to read after or just take a nice, well deserved nap. Try to have a relaxed mindset the entire session. Take a breather after a few difficult questions to unstress your head from a mind-melting question. Make sure you use good English grammar and spelling etiquette for any "short response" questions too, because sometimes they like to mess you over because of that. And also, try looking forward to the rest of your day following the exam!
Have fun and good luck! You will totally ACE it, with or without advice!! :)