nice advice Without Wings. I agree with you.
maths is a doing subject.
reading notes is berloody useless.
more maths you do, better you'll get.
on the other hand, you prolly dropped cause you weren't doing all the work.
:-\
read the theory, then try some past papers. If you get stuck on anything, go to your textbook, and do the ENTIRE exercise . . . you applicative knowledge of that particular section is weak. Get it strong.
that said, the best way is still do the latter half of all the sections you don't know.
your choice, it really depends on how much time you want to spend.