Make summary notes to the syllabus dot points. I type it up as i find it easier to add and revise the content i put in but its also not a bad idea to write it up manually. Also, for bio and chem do the exam qs in the textbook and all of the extended response ones. And for all 3 do as many past papers as you can. With general, go through your textbook and have a set of notes on formulas/examples on how to apply them, even though i think in general you get given a formula sheet, its better to know how to apply them so that in exams you are answering qs efficiently.
