You need to find what revision methods truly work for you but the most important thing is to know the content on YOUR specification INSIDE OUT. For subjects like maths and physics, practise questions are the MOST important. Do as many questions from as many sources including old spec past papers, new spec past papers, revision guides, textbooks. Isaac Physics has really good questions which can expose you to new scenarios you may not have seen before.
It's really not impossible with hard work, being on top of content from early, and those with great memories get a decent advantage at least at GCSE level.