I would suggest separating topics up and mind mapping the key points you need to know on them, then for key terms I suggest putting them onto flashcards and testing yourself. If you don't want to do this I would suggest using GoConqr as on there people make revision resources and then share them with everyone.
Or if you would not like to do that then I would get together a group of friends and all pick the topics you don't know much about or are finding hard. Then all make a presentation on the topic you are finding hard to your other friends. This helps because if you have to present it you have to understand it so you will go home and learn about the topic and then tell your friends about it. If you all don't understand the topic then all make a presentation each on the topic and compare notes once you have presented.
Sorry a lot of writing!!!!