If there is something you don't understand during lecture, ask me and I'll try to clear it up. If you miss class, get the lecture notes from a classmate before the next class. Review the notes for each class as soon after class as you can and expand on them. Indicate items in your notes that require clarifying and clear them up as quickly as possible. Don't put off memory work.
Repetition is the key to success with memorization.
Making and using flash cards is often a useful assist in memorization. Work as many problems as you can. Start with the in-chapter problems, and then do the problems at the end of the chapter. Practice helps to perfect your problem-solving skills. Finally, if there is something you don't understand, get help sooner rather than later, or it may become too late.