My suggestion is to annotate notes to help you understand certain concepts that you're having trouble holding onto. I also suggest that you highlight first aid. Read through it slowly, word by word, and ask yourself after each word (figuratively) "could I have guessed that if it was covered up?" If not, highlight it. If it's something that you've never heard of or just can't remember even when prompted with the term, highlight it in a different color so you know to spend extra time focusing on it.
I went so far as to create little "flaps" (with paper and tape) that covered key terms and facts that I had trouble remembering. That way, reading through the book was an active learning process where I actually had to think about what "XXXX" was, before opening up the flap covering the words to check myself. That sort of thing really gets your memory working, since if you just highlight a term that you keep forgetting, you never get a chance to try to remember what it is, because as soon as you've looked at the page, the answer is spoiled for you.
Might be a bit too much for most people, but I'm certainly happy with the result it gave me