1. Flashcard Cycling
When you use flashcards or study sites (like Quizlet) it's important to first target the words you know the least. Go through all of your cards once and try to verbalize the definition that's written on the back. If you get a card wrong, put it in one pile. For all you get correct, put into a "later" pile.
Now, separate the cards in the "wrong" pile into pairs or trios. Just focus on small stacks at a time; when you've memorized the cards in the small stack, add another two cards to the ones you've just learned. Do the same exercise with this new collection of four or five, and work your way through the "wrong" pile until you've memorized them all. After completing that, add the card you got correct the first time, and do a few rounds where you verbalize the definition of every word.
2. Rewrite your notes.
Rewriting (or typing) your notes forces you to read and process important information as you copy it to a new place. By writing your school notes/textbook notes, you review and summarize important points in your mind. This helps your mind to realize that "Hey, this information's important! Better put it someplace I can see it!" It's commonly believed that a person better understands a text or concept after the second or third reading.
So when you need to really understand a text, don't just skim it once and move on!
3. Study the same material multiple times leading up to your exam.
It can be easy to feel secure about your understanding and application of a formula or concept if you do well when you first learn it. However, given student workloads at colleges and universities, it's shocking how quickly we can forget the material we think we know.
To prevent an in-test meltdown, make sure to go back and review what you've learned every 2-3 weeks. This way, you can make sure nothing will catch you off guard when the test has begun.
4. Get enough sleep.
While this seems arbitrary, many students force themselves to stay up all night before an exam to cram. However, taking a test while they're so unrested will almost grantee worse results. Sleep is a time for your mind to process the information you've absorbed in the daytime, and going into an exam raw from studying won't allow the time for this.
There's also speculation that the best decision-making is done when fewer decisions have been made since waking, as your mind tires the more choices it makes over the course of the day. If you don't give yourself enough sleep, your mind can't properly rest, and your decision-making will suffer. Worst case scenario, you may even fall asleep during the exam. Just plan to study incrementally beforehand and get a good nights' rest.