Past papers are wonderful for practicing how the questions will be the exams. As well as knowing the information, you need to know how to answer the questions in the way the mark scheme wants.
Make notes from your school books and revision guides. Whether it be mind maps, pictures, timelines, whatever. Add colour and make it stand out. Shorten your notes down onto Flashcards to hell you remember the key points. Stick post-it notes around places you go all the time in your house for things like quotes for English.
Remember to spend time relaxing too. Don't get yourself in too deep that you lose the energy and motivation to revise.
Revise in 30 minute slots - a five minute break between the first two, then a ten minutes break. Repeat the cycle a few time. It's much better than revising for five hours straight and taking an hour's break afterwards.
In short, revise in ways that work for you, don't burn yourself out, and remember to take time to relax.