Revise anything you’re not confident about. Make a list of things you wouldn’t feel confident in if it came up on the exam (in my case, I have a list of topics I’d panic about if there was a question on the exam.) For the 2-3 days before the exam, cover these topics to consolidate your knowledge.
If you’re not feeling particularly worried about anything, go through the past exam questions that you’ve gotten wrong and identify which topics you make the most mistakes in. Focus on that topic, and try answering your mistakes again.
As a fellow year 11, good luck!!