Get off TSR and actually do some revision. Just think about opening your letter on results day to see awful results. If that feeling doesn't make you revise, nothing probably will.
Go through your text book. Choose maybe five topics that you are relatively unfamiliar with. Stick post-it notes on each paragraph or important section. Summarise it in bullet points. If you have time, make flashcards of these summaries. This, for me, is the best last-minute revision.