Data based on 3 reviews.
Revise the content you learn after each class for 10-15 minutes at home, and attempt to explain the theory and implementation to yourself. If you find a portion of the content confusing, or you can't explain how it works, read the textbook for your course, get the key, or see Mrs Heron before or after class. I did all of these and finished both chemistry classes I had with Mrs Heron with excellent marks.
Listen to the theory it will help in the long run