Yeah, don't revise stuff you can allready do, find out what you can do through past exam papers, if you can't do a question seek further questions in your textbook or online and do them 'till you have it down. Don't do loads of work all at once, break it down, 30 minute sessions every other day are better than 3 hours solid at once. I find two sessions of about an hour in a week per subject works pretty well if I start a few weeks in advance of study leave (bit late now, for you, but next time), it really does ease the stress.