Hi, I got 9s in Biology, Chemistry, Physics (AQA) and Maths (Edexcel) - I didn’t take further maths though, sorry.
For science I basically worked from the CGP revision guides - made flashcards on everything and tested myself loads. It’s important to make sure you really understand a topic, though - it’s much better than rote learning things. I found free science lessons really good for quick, easy explanations of topics - and the required practical videos are really good to recap your knowledge.
Make sure you are familiar with all the required practicals in detail - I wrote out the method for each one, identifying the variables and common errors. There’s almost always a six-mark ‘write a method’ / ‘design an investigation’ question.
Practice exam questions are really useful - mark them yourself to familiarise yourself with the mark schemes.
My school used to give us revision checklists from Kerboodle - personally I found them really wordy and confusing, so I would always check the exam specification instead to make sure I’d covered everything in a topic.
For maths I think the best thing to do is practice papers, where you can identify your weak topics and work on them. Maths Genie has some great revision questions for specific topics.
I hope this was useful - good luck for all your exams and don’t overwork yourself
It’s important to take breaks regularly, otherwise I found I was much less productive.