I would honestly try explaining a topic to one of your friends, writing out your thought process for a specific question on a whiteboard and basically "teaching" them how to do it. Then they can give comments as you go, which will allow both of you to better understand a topic.
I also suggest using videos for certain topics, like the ones on save my exams and try different ways of understanding concepts.
Maybe try completing some past paper questions under timed conditions to see if this has an impact. If it does, practice this and get more used to the time pressure and stress of exam conditions.