Ask for clarification. Don't let anxiety build up because you aren't sure about some parts of the test. Pay attention to the test, not to yourself or others. Avoid doubting yourself, wondering how other people are doing, or blaming yourself. Pay attention to what you CAN do now.
Activity reduces anxiety.
If you go blank and can't think of anything to write, go to another question or another part of the test. Relax yourself physically during the test. Concentrate on your breathing. I am proud of my effort today on this exam. I can and will remember what I know.