I prefer to make sure I understand the stuff as I go through the course, then just do some practice papers before exams to make sure I know how the exam will be structured, and haven't forgotten anything major. Sometimes I stretch to looking at summaries in books, but that isn't absolutely necessary if I have somehow managed to keep on top of things.
One thing I absolutely never let myself do is get all worried about the exam. It just makes it so that I can't work at all, and I'd rather keep myself in a state where I do have a hope of passing that put lots of unnecessary pressure on myself. If I fail I can sort it out afterwards, not the end of the world.