Close your book, grab a blank sheet of paper and draw a diagram that shows the steps in a process - then check your work. Try some of the review questions in your text book - ask your instructor which questions are good and which are too detailed. A blank sheet of paper is one of the greatest study tools of all time. Then check your work. Study the details you forgot, then try again the next day with another blank sheet of paper.
Memorization is just the first step.
Memorizing the parts of a car's engine won't give you a full understanding of how it works, and certainly won't prepare you build your own car. There is a large quantity of information that you'll have to memorize to succeed in biology classes, but memorizing is not the same a learning. In the typical introductory biology class you'll learn as many new words as in a foreign language class. Some people make the mistake of relying on flash cards as their only study method. Flash cards may help, but only to a point.