Greetings,
Good tips from SAYA - especially number one.
One of my old professors gave me a tip for exams which I have never forgotten. It's really suited to essay type subjects rather than factual questions. Here is the advice:
Get angry about it. Get angry about the fact that you have to submit to the performance of doing an exam. Believe it or not, you nearly always write better when you're angry.
Although I'm not an angry or violent person, I used to love doing exams using this approach. I would imagine the exam as being almost like a fight between me and the examiner. I would prepare over a long period of time, gathering knowledge to make sure I wouldn't be beaten. Then, on the day of the exam, I would work myself up and walk in thinking "Do your worst, Mr. Examiner!"
I know this sounds like a strange method, but it always worked for me, and many students I've taught over the years have found it helpful too.
Peace