I really don't study for upcoming exams. I mostly rely on stock knowledge (what I remember, and what I heard in class lessons) and a few practices I commit to before an exam - such as sleep early and wake up early as well, do a light reading/skimming of subject material (refreshing memory) for a few minutes, then eat a good hearty breakfast and get to school early.
My mother always end up admonishing me for not studying at home, then says nothing when I get all A's. Bummer.