The most important resource you have is time. Organize it! You know studying a little bit each day is a better option than waiting until the last minute. Check out this study calendar you can customize.
When's the last time you looked at the bottom of your locker, in the back of your folder, side pocket of your backpack or at past pages of notes? Before re-reading your textbook or notes, get organized. Separate your materials by class and group them together. Put them in the order in which you did them in class. Label things with chapter names, unit titles, key words or concepts.