Well, it depends on the subject. e.g for Maths I complete past papers or for English I'd revisit my essays. but for all the days b4 an exam I. try to sleep early (??) around 10-11 pm? One of the worst things I found for myself is cramming all night.
I agree that it depends on the subject. But generally, I read through my notes a couple times, and look at my syllabus making sure I can recall everything. Then practice questions, then past papers in timed conditions.
The day before the exam, I go to bed early. Then I wake up and try to think positive so that negative thoughts don't affect my performance. A good breakfast is also helpful.