There are many ways of studying for exams, but the following is an especially effective one. First and most importantly, listen closely to what the instructor says. She may tell you which sections to concentrate on, which to leave out, and which topics are sure to be tested. These should receive your foremost attention.
Ideally, you have been studying for the exam daily during the presentation of the course material. Realistically, though, you should at least begin preparing for the exam about a week before. Buy some index cards, or just cut up pieces of notebook or typing paper in small squares. Begin with your class notes, and write everything on them in the form of a question, with the answer on the back. If you have important reading notes, do the same with these. You may learn the material by writing it a second time. You should try to read all the assigned chapters, or at least the sections your teacher emphasized during lecture.
At least two or three days before the test, you should start going through your question cards. If you know the answer to the card, set it in one pile. If you don’t, set the card in a pile to go through again and again until you know it. When you get down to a few facts that your brain stubbornly refuses to learn, write them down on a page of “Things I Didn’t Know,” and think about them carefully. Find a way to remember them. One helpful trick is to draw a silly picture (like a characterization of a hormone performing its function). The sillier it is, the more likely you will remember it and be able to picture it on exam day. Also helpful are creating mnemonic devices (like “On Old Olympus’ Towering Tops” for memorizing cranial nerves I-V), and writing your facts again and again as simply as possible to increase retention.
You should, at the very least, make sure you know everything on your question cards before the exam. Next, reread your class notes, and you will start to understand how everything fits together. If you have more time, you can go through the cards again, study your page of “Things I Didn’t Know,” and reread the pages in the book. Sometimes it helps to go through all the diagrams and pictures in the chapters right before the exam, to cement your knowledge, and to be prepared for questions that might come from these sources. (If you note after the exam that your teacher likes to make questions from the book’s pictures and diagrams, be sure to include these in your study for every subsequent exam from the same professor!)