Knowing how you best learn is a good start. That helps me in all subjects. If my teacher doesn't teach in my "learning style" I adapt by other means. If I have difficulty with a specific concept I search educational websites for interactive learning tools. i.e., self-quizzes, animations with audio, even games that reinforce the study material. The more senses I engage, the better I retain. Ex: Read out loud when you read, when possible. Also, sometimes one "presenter" of information, as opposed to another, will break it down in a way that you may find easier to absorb. Lots of universities have accesible science department sites. Study chapter reviews in your text. Know how to answer those questions. I've even been known to consult "For Dummies" books. Find a study buddy or a supportive person who is willing to ask you questions to see just how much you are retaining. This will flesh out where you are strong and where you are weak. Lastly, devote enough time. Other posters have great suggestions. These are things that have helped me, and I hope they help you, too. Good luck!