I started revising around about now, Easter is when most people start revising for their GCSEs, ASs and A2s.
What I did was got these little revision books and wrote out notes from those CGP books into them.
I did that about everyday from about now until the exams for atleast 1 hour a night. But break the revision into little chunks like 20 minutes, you'll get a lot more done in 20 minutes than sitting down for 2-3 hours and getting bored and starting going on the PC or watching telly.
Good luck