just study... well, at this point you're just memorizing.
But, writing everything down over and over and repeating it will help you memorize little facts, which, are usually the most valuable on a test. dont' worry about memorizing the whole thing, either. just memorize something small about the bigger concept and by recalling that, you'll be able to get the whole concept.
Study the stuff you know will be on the test first. then concentrate on the stuff that you know pretty well.
before the test, take out some paper and write everything that you know down.. it will help you be confident.