I make sure to study a bit each day. I go after my lecture note on the same day I had class and fill in extra info I get from my textbooks and lab manuals. I study from all my homework assignments and form a study group a few days before the exam so we can all take turns teaching material to each other.

And this sounds bad, but I tend to drink energy drinks and take caffeine pills and ginseng to induce a hypomanic state of mind the night before and day of the exam. I find I am just so much more clear headed when I take an exam in this state, I used to ace exams like this by just cramming the night before the exam. Of course this is a controversial but personal choice.