Hey, I got an A* in Politics last year, and I started properly revising around this point in the year.
My main revision resource for papers 1 and 2 were essay plans - I used essay banks provided to me by my teacher (ask for lists of possible questions if you haven’t already) plus Mr Patel A Level Politics predictions to write a tonne of essay plans, including I believe about 3-4 examples/counterexamples per paragraph. I then memorised these by using a whiteboard and writing them down from memory in a look cover check fashion, then when I felt confident with that I got people to test me.
Although in the exam I was faced with a few times (although not many) where I had to choose between two questions I had not planned for, even then I could use the examples I’d committed to memory to write the essay in the moment. Use the specification like a checklist and make sure you have at least a little bit of knowledge on things even if you think they’re not going to come up - everyone thought the Lib Dem’s wouldn’t come up, so it was a bit of shock when they appeared on the paper in front of me in my exam!
Paper 3 (global) was a little different, as it was the synoptic paper - as they could combine any two or more topics together to make a question, there were too many possible questions to make plans for overall, and I found this paper quite tricky as it seemed to have far more content to cover individually than papers 1 and 2. Therefore, I changed strategy and decided to make broader fact sheets for each topic with a list of examples I could use, and any possible analysis I could think to give them, which I again tried to recite to memory using my usual methods.
The one thing I wish I could have done differently leading up to the exams is more essay writing prep - I would really encourage you to write just one essay a week, just 30-50 minutes of your day, because under stress it’s very easy to run out of time without good practice. Plus you could give them to your teacher to mark if they’re not too busy and get some valuable feedback.
Sorry for the long message, hope this helps a little