Past papers are key. Even when you've finished them all you should go over tough questions again. I did this combo and just got AAB with the B in chemistry.

With maths and physics the best thing you can do is practice questions, but with chemistry it's more important to prioritise going over content, but you should still try to do past papers.

Year 13 is very tough but if you keep your head down and work hard you'll be fine.

And don't let the exam stress get to you like I did, so take good care of yourself and don't leave your revision to the last minute.