Studying

How do you guys study for science/math tests or exams? Best method? And how many days in advance do ya'll start to study?

I dunno about you guys, but I avtually need to study to do well in a class.  for this, what I do is do my homework and instead of using my notes directly when I have trouble with a problem, I look up what I need and then write it on a sheet of paper.  by the time the test comes around, all the stuff I was having trouble with is on a few sheets, and I can review them and write a note sheet quickly and easily.