hi there, im 1 yr above and i did re and maths too
For maths, I'd suggest you to make all your notes and examples really neat and to practice. Not like every day but like once a week, covering certain topics. Make sure you revisit any old topics so u eventually master it all. Practice is the key for a level maths. Use the maths spec wisely to ur advantage and before ur ucas exams start doing past papers for AS and yr1 maths papers.
For RS, you can chill. Learn the theory and be able to apply it easily into different situations. Learn your terminology and keep ur philosophy, ethics and christian deontology sections seperated into dif folders so its easier to use when revising. Learn bible quotes every two weeks for the dif subjects in christian deontology and make sure u plan out all the stuff covered in philosophy and ethics and learn to critique certain theories.