Try to maintain as normal a schedule as possible. Of course you want to study more than you normally would— definitely set aside extra time in your schedule to study for your exam. But remember to set aside time to sleep, eat, exercise, and relax, too. Start studying a couple of weeks before your exam; think about 5 days of study per class. This way you're not cramming and forgoing everything else in your normal schedule. (Which brings us to our next point:)
Review regularly throughout the semester. This is the only real way to avoid cramming and still get a good grade. Read, study, and memorize terms at least once a week through the semester (even more often, if possible). That way you have less information to cram in before the exam. At the very least, start picking up your study game for the couple of weeks leading up to your exam. Give yourself a few study days (optimally 5) for each class. Follow the tips in the Studying page for the weeks leading up to the exam, and you'll be better prepared.
Studying by just re-reading your notes and the text gets boring, and it's usually not enough to ace an exam. You should review notes and the text, but then follow that up with ways to really absorb the information. Follow some tips on the Studying page to absorb the information in new ways. These include concept mapping, creating diagrams, and even writing summaries of what you know. Use the study techniques that you know have already worked for you. Think from the instructor's point of view, go over things you think they would ask, and use sample questions they give you.
Think about what you will have to "do" on the exam and this will tell you what you have to "do" to study.
(Maybe you just noticed that one thing all kinds of tests require for you to do when studying is to test yourself and use retrieval practice...)
While studying, test your knowledge out loud using self-quizzes or flashcards. Reciting the questions and answers out loud helps you retain the information using more than one learning style. Before your exam, recall information and put it on paper from memory in the form of summaries, diagrams, outlines, etc. This is called "retrieval practice," when you are actively recalling information. This drives the information home and makes it easier to recall later, during the actual test. Check to see what you're missing and make sure you go over those points.
Consider your weaknesses. For example, if you remember and understand the vocabulary but have a hard time with concepts and theories, go over them again in a new way until it's clear. Ask your professor, teacher's aide, or classmates to explain something that's unclear to you in a different way. Don't gamble on just knowing the material; make sure you've mastered it.
If your instructor gives you a practice exam, use it to practice taking the test. If they didn't provide one, try using any sample prompts or questions they've asked. Only use the materials you will be allowed to use for the real test, and try to imitate the testing conditions (practice at a desk using pen and paper or on your computer). When you take a practice test after studying, you're using "retrieval practice" again. Make sure you really understand the information in case the instructor rephrases the questions.
Be kind to yourself. Take breaks while studying, eat healthy foods, meditate, practice deep breathing exercises, and don't pull all-nighters. If you need help, go to the Coping in College resources section of our Mental Health guide.
Make sure you get a good night's sleep before your exam. (Or if you really feel like you have to cram, at least get in one good sleep cycle instead of the several you go through in a given night.) Sleeping after studying helps store the information in your long-term memory instead of only keeping it in your short-term memory. (True fact!) And watch your caffeine intake while you're studying; drink too much of it and you might have trouble getting some sleep.
Also eat a good nutritious breakfast before the exam, and stay hydrated. You don't want to be foggy or distracted by stomach rumbles and hunger pangs.