I tutored students for a while and the biggest advice that I can give is to understand why. The whole time you are studying, constantly ask yourself why. When you understand why something happens, you will know it enough to ace the test. Also, look at your previous tests. Did you start to perform poorly after a question that you didn't understand well? A lot of times students will put a lot of pressure on themselves to do well and so when the come upon a question that they don't know, they become unsettled and it messes them up. I would advise you to only answer the questions that you are sure you know the answer to right away, then move to questions that you kinda know the answer to, and so on and so forth, moving from the easiest questions to the hardest. If you start freaking out in the middle of a test, put your pencil down, close your eyes, and do some progressive relaxation or something for a couple seconds. If you are not calm a relaxed, you will make stupid mistakes that will cost you points. Also, if your professor gives you last year's test, you have hit the mother-load. The will test the same concepts every year. As you are looking through the old test, understand why the right answer was right, and why all the wrong ones were wrong. You won't get the same question on your test, but you will get something like it. These are easy, free points.