I would definitely recommend making mind maps and doing practice questions/ papers. Looking at the feedback for the previous years can also be really helpful (you should be able to find this on the website). I also revision websites really good, especially bbc bitesize and some really good quizzes have been made on quizlet too.
Also the spec online can be really helpful and after a bit of digging you can find past student papers that can be helpful too. Don't be afraid to ask your teacher for help too, I'm sure they want you to succeed.
Hope this helps,