i agree with most of the above. defo do homework as soon as u get it, that way u keep on top of everything. get a diary and write down every piece of hw u get. dont do the bare minimum, do a bit extra if u can. what i used to do after id done all my hw/revision was write in the space in my hw diary for the next day all the revision i wanted to do and then add my hw to it as i got it which helped me be prepared for the next day.
revise continually id say. give urself a break in june tho, but do all ur hw and maybe do some revision before u go back in august. keep going to school up to the last day! (well as long as u know ur teachers will def be teaching anyway). even if u dont have a test coming up, revise something ur unsure of, ull feel good about urself and ull be a step ahead! when u find out u have a test work out a study plan. the way i did it was if i had say 20 pages of notes to learn in 10 days id learn two pages a night and break it up like that, up to u how u do it tho.
have an organised set of notes for every subject. if ur teacher doesnt give u any get some from the net/books.
stay motivated, its only a year out ur life and its def worth all the hard work. plan a day off every so often to give urself a break. have a goal- getting into a particular course/uni and whenever u feel urself flagging think about tht and how fab it would be. i desperately wanted to do medicine and that desire kept me going all thro fifth year.
i would say tho that if u dont work and then get rubbish prelim marks then that is TOO LATE to start working. a friend of mine wanted five As, got rubbish prelim marks, worked hard but still fell far below her target.
i didnt find them as bad as everyone made out they were. but i did int 2 instead of sg so maybe thats why. be organised, motivated,work hard, and ull do really well!! good luck!!