Relax on campus immediately before the test, perhaps with the newspaper and a cup of coffee. Don't study the last hour before the test. Eat something light to give you energy and to keep your stomach from annoying you as well as others. Blackboard is in view. Clock is in view.
Light is okay.
Distracting friends are not near you. Relax for a second before starting. Practice slow, deep breathing. Some anxiety is good for motivation. If you have too much anxiety.