If you're in college I know midterms are coming up. And if you're not in college, well I'm sure you still have to take exams. I know, MOST people hate taking exams. Some people do really bad on exams but are really good students overall. DON'T STRESS SO MUCH!
It's very important to study, you can't expect to do well on the exam without any knowledge of the material. Some people could just pay attention in class, memorize what the teacher is saying and they don't have to study. However the textbook usually goes more into depth. Not ALL the questions are from what the teacher says. Make sure you read the textbook and study your notes along with anything else your teacher handed out to you. Sometimes it's also better to study in groups (more so for college students). You can help each other out and answer each other's questions. I personally have found group studying the best way to study. However, don't start studying the night before! You'll be cramming. You'll get the material all mixed up, and you most definitely won't get a good nights sleep which is another important thing!
You don't want to go to class tired! You'll probably fall asleep during the exam! (I've done that a few times), not the smartest thing to do! Even if you're drinking a cup of coffee! Coffee doesn't even keep some people awake (like me.. it does nothing for me!).... and others ... well they'll be bouncing off the walls especially if they're adding sugar. Anyways, the point is... you want to be well rested. You want to know your material inside out... but you also don't want to be tired for your exam.
Pack your bags the night before! Make sure you have #2 pencils as is required for most of the exams since scantrons only accept #2 pencils! You don't want to be the one person in class asking around for a pencil because you forgot yours. Be prepared! Bring more than one! Also.. if it's a math exam, don't forget your calculators!
Bring a bottle of water! What if you get thirsty during your test, or even before from all the nervousness! But don't keep it on your desk, you don't want to accidentally spill it!
"To accomplish great things, we must not only act, but also dream, not only plan but also believe."
Best wishes for your exam!