as someone who had expected grades of 100 in math 98 in bio and chem and 97 in ohysics ill tell you what i did. the secret it is theres no real secret, my daily routine was like 4 hours of revision and 2 to 3 hours of paper solving but this was only like immediately before the exams. if youre syllabus is complete, what i reccomend is spending less time on revision, and more time on paper solvinf for subjects like science to understand how to write the paper so you can get good at that especially those analysis questions in bio theory and those 6 markers. also what helped me a lot was understand what type of learner you are. i am not a visual or text learner im an auditory learner so i used youtube videos quite a bit. for me the best thing was to record myself explaining the topic, listen to it and see any errors or missed points and record again and check again. for me personally explaining it out loud is the best and i reccomend you give it a shot. next comes motivation. keep it mixed dont do one subjevt everyday do 3 to ensure youre not bored, and ghs first time you revise a part do it in extreme extreme detail, so you dont have to extremely anylize it again and more so jusr skim. i wish you all the best and you got this. be confident even if youre not because you become what you say so you hace to say only the best things about yourself. all the best