when it comes to maths, you have to solve a lot. That is the case for all maths a levels regardless of the exam board. Start with the topics you are less confident in, and keep solving until you are getting most questions correct. The topics that you understand better won't need as much time. Just solve from each topic until you are confident AND when you notice that question styles are being repeated and there are no new ideas. You should also be solving most questions from the AQA maths book before this step. Hope this helps.