I agree with j0n, it really does depend on how you feel you learn best, and he basically sums that up for you. Whatever method of studying you choose, you should always make sure you don't overwork yourself either. Take breaks from long study sessions, just don't get around any TV's or your computer, as they can distract you (assuming you aren't using it to study of course). Make sure you get good sleep too, especially before your exams, most of your memories actually "file" themselves in your sleep. Plus, a rejuvenated brain functions much better than a tired one. One thing that helps me, I set incentives for doing the work. Whether it be setting goals with small rewards for yourself (candy, breaks etc. etc.), or simply telling yourself that you can't do something you like until you finish (such as coming on DC or working on your redstone tutorials.)
I must say, its good that you're seeking these tips so soon in your "educational career." When you get to the later years of school, when everything is more advanced, they will help a lot. Especially if you have one of those schools that has a massive "final year" project.
I wish you the best of luck in exams, remember to have confidence in yourself. Study hard!
~Scoobs