I got 10 A*s (english lit and lang, maths, french, spanish, latin, bio, chem, physics, geog) and 3 As (FSMQ, polish and history)
I guess I revised quite hard in the lead up - all my notes were finished for my mocks so I just had to update and improve them for the real thing.
However the night before some exams e.g. the additional science exams I barley revised at all, I think I was just all burnt out and just left the actual learning to the morning before if the exam was in the afternoon. For my extension science units I tried my hardest to revise as much as possible because I didn't want bad add results to drag me down.