For maths, English, and sciences our teachers have been giving us a past paper to complete over each holiday, and on other subjects we've done select questions from past papers throughout the year. If your teachers haven't been doing something similar and the only past papers you've seen were in the mocks, then I'd strongly recommend starting using them now.
Here's what I do when given a paper to complete:
Revise all content of that paper's topic (eg b1 b2 b3 for a biology paper) using your preferred revision method/methods (eg videos, revision cards, etc) - make sure to do active revision where you test yourself as you learn (eg using the questions in the revision guides or on bbc bitesize) rather than passive revision where you just read stuff but don't actually take it in.
My preferred method of revising a topic is to go through the revision guide and as i go along i create a revision card/cards summarising all relevant information on each page. If the topic is particularly hard then i also watch a video and make notes (making notes helps to embed the content of the video into your memory).
Next, do the past paper in timed conditions, in one sitting if at all possible.
Once you've completed the paper, mark it.
Now go over the marked paper and look at all of the questions you got wrong. Go back and revise on the things you got wrong, making sure that you now know the content. Do you know why you got them wrong? Will you get them right next time? Do practice questions, watch videos, etc, whatever you find necessary (as long as it's ACTIVE).
Now do another paper, mark it, etc etc. Repeat until you're getting top marks on each paper.
That's it! Obviously this is going to take some time, so spread out over however many days, but considering exams are drawing near remember that it's more important to cover all of the topics a bit, rather than just two or three on detail, so don't do this whole system for each topic of you don't have time, and ensure you spread out your revision amongst all subjects, with English, maths, and science taking priority.