practice exam questions and nothing else. do them with a textbook and class notes until you remember it. i wasted so much time copying notes from the textbook at gcse and it really didn't help at all. trust me exam practice is how those smart kids in your class get 9s. it's the only way.
as for english, for literature, always refer to context in EVERY point you make, not just at the end. say how a reader or whoever would've felt about this at the time. always use quotes. dont be shy to say how the part your making a point about made YOU feel as a reader. talk about how each word (adjective, noun, adverb etc..) changes the meaning and the tone of what you're writing about. never make a point if you cannot back it up
for poetry just try to remember quotes from two of each genre, you don't need anything else.