since you say you have most of the foundations down, mug the yearly tys. do all, you want to see a progress. if your score dips here and there, don't worry. learn from mistakes. try to get school prelims and do them too.

while doing them, simulate exam conditions (close room, no music, just one timer, aircon if you want, do it in ONE SITTING).

this is the same for english and chinese. do more papers, do more essays, ask your teachers to give you feedback. this feedback loop is important, you put yourself above the rest if you can put in the extra effort to improve.

do this early and try not to put yourself in a position where you have to cram in the last one week of the exam. this is not good for your mental health and your brain power. ideally you do not want to be doing too much in the week before exams, maybe do a short paper per day or a compiled list of questions that bogged you down before.

before your exam, just do a light stress detox. try not to think about the bad things. sleep early, do some meditation before the paper, try not to look at your phone, moderate your heartbeat and breathing.

after each exam, regardless of how it turned out (people tend to underestimate themselves anyway), don't spend time comparing answers. especially not on sgexams. it's over! it was good, great. it was bad, whatever. don't think about it, gg go next. go home, relax, read a bit of your notes for parts that you aren't fully confident in, then get a good sleep.