I read everything and take notes as I read before class on the topic. I do all the questions at the end of the chapter, all the questions in the workbook, and all the questions from the Success series (I'm using Fundamentals Success this semester). Then I re-read all the chapters before the exam. It is a lot of effort, but it pays off.
Also, when I take notes about a person or numbers, I make a special separate notes consisting of numbers and people (the things hard for me to remember).