My biggest piece of advice as someone who has just finished Year 13 is to be organised. Use your time wisely and find your own way to manage your time e.g. schedule, diary etc. I have learnt that all the effort you put into Years 12 and 13 all go towards your final grades and it's not a case of doing two months of revision before your exams.
I would recommend that you make sure you have a good revision/study method. Make sure in every lesson you understand the topic as this will help you remember things better. After a lesson/during the week, watch a Youtube video and make notes on the topic(s)/Quizlet flash cards. You can also find premade flashcards on Quizlet or Physics and Maths Tutor (not just for Physics and Maths). Regularly review your flashcards to keep them fresh in your mind. Practise questions from Physics and Maths Tutor. Use the specification to make sure you understand everything. If you get an exam question wrong, make sure you understand why you got it wrong and add it to your notes/flashcards.
This is just my advice and seems to have helped me with my STEM subjects. I have also found that the more times you go over revision material the better you will understand it. Make sure you also have time for yourself and don't burn yourself out. This is why I would highly recommend that you stick to a schedule that works for you that enables you to study effectively and look after your mental health. Hope this helps and good luck. What subjects are you taking?