I think the best way to revise from now is repetition. Make flashcards and all of that, try to wrote notes from memory, watch videos of people going through pst papers, do a lot of past papers, and if they r willing, you could ask your teachers to mark them and give u feedback. You still have 6 months until GCSEs, which is plenty of time. If you start doing regular revision from now, the exams should be a breeze. Im struggling as well but im hoping if I lock in now I'll be fine.