Don't want to jinx Thursday but I'm predicted 3 A* (plus some unknown pointless and obscure grade for general studies) so just thought I'd share my experience.
Honestly with A levels the exams are so generic a tick box approach to revision really does take you far, despite how teachers will tell you to do extra reading etc. best advice as some have said is past papers (I do history philosophy and eng lit so this does work for essay subjects too- got A* in my only jan exam). Obviously if want 100UMS then cramming like me probably isn't the answer, but I'd be ecstatic with A*s as most people would be!
Seriously don't stress too much over revision it's not worth it, and if your friends are telling you in march April that their revising then their lying- no one starts that early, and if they do they'll forget or by the time the exam comes round.
Im sure you'll do brilliantly, best advice is past papers and lots of timed essays before the exams as this is often the hardest part, the strict timing.