If you don't get it now, you won't remember it for a test. Take as much time as you need to answer your questions. Don't be frustrated, this takes more time but the information will be clearer in your mind. Keep rereading your margin notes and underlinings. Verbalize the sequence of main ideas and supporting facts to aid retention.
Numerous reviews are a lot more effective than one cramming session the night before an exam.
Review once right after you've finished reading and then every couple of days. The SQ3R is time consuming at first, expect it to take ten to fifteen percent longer to read a given chapter when you first begin. The most comprehensive note taking systems require attention on your part. You must be alert enough in class to take legible, meaningful notes. If you have problems determining the specific relevant points in a particular class, you can always ask the professor to clarify them for you.