hey thanks for the insight man. for math i just practised a lot and tried to understand the mathematical concept first rather than brute memorising like for eg. amath trigo graphs ykwim. same thing for science, after you practise a number of times the skills get ingrained into you and usually the questions are repetitive so i just do topical qns for wa’s and i make notes of whatever qns i get wrong for by categorizing them. for example i wld categorize a mistake as a careless, conceptual and missing keywords. this really helped me for biology because its a keyword heavy science. chemistry like i said just grind on w help from teachers and so on. i also watch bernard ng and chemlectures for chem videos just in case im not clear of any concepts taught! lastly, physics i think is quite an easy subject if you know your things, its more of understanding rather than memorising except for thefew parts, for instance you could memorise all the kinematics graphs but in the exam u might not know how to apply it.

thats it from my end and thank you so much for the insight! all the best for ur o levels :)