I got 8A*s and 3As, and I'm not really that clever, it was mainly from hard work!! My main tips would be to use 8tracks for study playlists because revision can be very tedious! Also, if you're doing languages, use Quizlet and just make 10 or so flashcards a day on vocab and test yourself using the games - this helped me loads!! Also, don't be afraid of asking your teachers lots of questions, I did loads and probably annoyed a few of them but they're there to help so never go home not understanding something! If you're doing Geography or History, start revision early, probably just after Christmas as it takes a huge amount of pressure off when you come to do the actual exams! Also, try a mixture of methods - sticking big posters on your walls of things you find hard to remember, create loads of flashcards, mind maps (which work brilliantly!), write things out in coloured pens etc because this helps to get the information into your brain. I'd say past papers are easiest and most efficient for maths and science and will help an awful lot. Everyone says you should do them for every subject (I didn't!) so it is probably best to! Hope this helps, sorry for the rambling!