Budget your time, make sure you have sufficient time to study so that you are well prepared for the test.
Go to review sessions, pay attention to hints that the instructor may give about the test. Take notes and ask questions about items you may be confused about.
Ask the instructor to specify the areas that will be emphasized on the test.
Make sure you go to the class right before the test; it's another prime time for the instructor to give out more hints or the format of the test.
Go over any material from practice tests, HW's, sample problems, review material, the textbook, class notes...
Eat before a test. Having food in your stomach will give you energy and help you focus but avoid heavy foods which can make you groggy.
Don't try to pull an all nighter. Get at least 3 hours of sleep before the test (normally 8 hours of sleep a night is recommended but if you are short on time, get at least 3 hours so that you'll be well rested enough to focus during the test).
Put the main ideas/information/formulas onto a sheet that can be quickly reviewed many times, this makes it easier to retain the key concepts that will be on the test.
Try to show up at least 5 minutes before the test will start.
Set your alarm and have a backup alarm set as well.
Go to the bathroom before walking into the exam room. You don't want to waste anytime worrying about your bodily needs during the test.