Repeat a concept out loud until you know it, then say it five more times. Write it down. Our muscles have better memories than our heads. Note-taking is a muscle activity. Extend this technique by writing a note not just once, but many times.
Writing uses different memory than speaking.
Writing is physical, using your arm, your hand, and your fingers. You remember what you do. The smartest students keep compressing their notes into smaller and smaller size. As they understand relationships between one week's work and the next, they consolidate and organize. Once a week, consolidate that week's notes.