Hey if you're doing AQA just get the AQA revision guides!
Also, check out free science lessons and my gcse science for triple science. Free science lessons especially is AMAZING!
You could also make revision cards... use websites like kahoot to make science quizzes (I had to do this at gcse). I recommend doing PAST PAPERS for science; it really helps!
Exam technique is VERY important!
Combining all these revision resources together should hopefully be enough to achieve a respectable A/A*!
I've also heard that CGP revision guides are very good. I never used them for gcse- but I have one for a level chem and they are VERY useful!