I have my personal method for memory and it served me well for now. When you are reading book read chapter title than take couple minutes and think "How/why would I do that".
Examples: "Linear systems with 2 variables" just think about it builds you understanding and it is easier to remember something you understand. Than you read chapter and get second opinion on problem. Bonus point if book has exercises on end of chapter. Then after thinking and before reading go to last exercise in chapter and read it, to answer "why" question, best exercises for this are "Alice have 3 apples ..." style exercises. Try to solve it before reading.
This method works best for STEM books, but it can be fun to try it on history, fantasy books if the have spoliery chapter titles.
Examples: "Linear systems with 2 variables" just think about it builds you understanding and it is easier to remember something you understand. Than you read chapter and get second opinion on problem. Bonus point if book has exercises on end of chapter. Then after thinking and before reading go to last exercise in chapter and read it, to answer "why" question, best exercises for this are "Alice have 3 apples ..." style exercises. Try to solve it before reading.
This method works best for STEM books, but it can be fun to try it on history, fantasy books if the have spoliery chapter titles.