Through the year I always attempt the problem sheets, and attend as many lectures and tutorials as I can. At the start of the term I try to read through the day's notes, and annotate them with explanations of anything that isn't immediately straight forward, but I'll admit, I usually fall behind in this as the term progresses, and towards the last few weeks, I barely do anything besides turning up for lectures...
And then when it comes to study leave/exam time, I end up skimmimng through the whole course and retrying every problem sheet/ doing any past papers that are available.