You may have heard that people who are drowning see their whole lives "flash before their eyes" in a few seconds. Although that may be an exaggeration, it shows how fast our minds can work. Your textbook (or your study sheets) is the way the whole course can flash before your eyes right before the final exam. For it to do so, however, you must have prepared your book and your mind for the occasion.
Imagine a page in a new textbook. The first time through, you made a cursory glance at the page doing your survey. The second time through, you read the material rapidly in order to get a general idea of what it's about. The third time through, you studied the page and distinctively marked a few key words, one or two phrases that summarize the main idea, and one or two sentences that explain and/or illustrate the main idea. Then, during review, you first look at the marked word(s), then the marked phrase(s), and then the sentence(s). With practice, a glance at the word will instantly refresh your memory of the page.
I have never found a freshman who hit upon this study tactic independently, and I have never found a student who really tried it and didn't like it. Periodically, at least once a week, start at the first page of the textbook and page through it up to the new section you are studying. The number of pages you must review gets larger as the term passes, but the time required for each page gets shorter the more times you've done it. Near the end of the term, you should be able to go through the early pages as fast as your fingers can turn the pages.
There is a subsidiary advantage to this textbook study tactic. Although authors try to arrange the material in a coherent order, so that each idea builds up to subsequent ideas, later ideas often help improve your understanding of the earlier ones. Hence during regular review, you are integrating the ideas into a more comprehensive view of the whole subject.
Most students get a chuckle out of one of my true-or-false exam items: "One should not be naked while studying." It could be a false statement IF one were willing to be naked when taking the exam! This item makes the important point that you remember what you learn best the more similar the learning context is to the testing context. At the same time, if you study in a variety of contexts, you are better able to remember in various contexts. Also realize that the context includes your internal state such as hunger and test anxiety, as well as time-of-day and the seat you sit in during lecture.
One final note about your textbook. Sometimes what it says is different from what your professor said in lecture. Which should you believe? Recall that even the most current textbook was written over a year earlier and new discoveries may have occurred in that time. Your professor should have up-to-date knowledge, and therefore her or his statements are likely to be more correct. However, if the professor doesn't point out the discrepancy in class, he or she will be happy to answer your question about it. Even so, you should be ready to answer exam items that begin, "According to the text..."