Adv. Eng: Read all texts, practice creative writing and essay writing, past papers
Biology: Past paper questions
Chemistry: Revise prelim work (just some parts e.g. solubility rules, mole calculations, etc.), past paper questions
Math/Ext. Math: Past papers, exercises from Cambridge for revision
SOR 1: Read relevant textbook pages, memorise examples
And of course write notes for the first topic of each subject and homework. One of my teachers suggested doing 14 hours of study everyday. Idk if he was joking...