I didn't see it mentioned anywhere on this page, but for memorizing, there is one very important insight. How well you remember something directly correlates with how interesting and important you find it. As if your brain is a cache that evicts data based on this priority. If you manage to manipulate yourself into believing that the study material is very important, you can memorize incredible amounts of data. Well, the optimal case would be if it's actually important stuff, of course! If you start thinking "why does this even matter", the memories instantly start to decompose.
Also, at uni, I learned that taking notes in maths classes is a recipe for disaster. How come? The mere act of writing down and arranging formulas on my sheet takes enough thinking power that I can no longer follow the lecture. What's better, having one single good shot at understanding things, or having not understood things and the incomprehensible scribbling of your notes also makes zero sense without the professor's explanation? The former for me. As long as I know the broad subject names, I can read up on my own.
One way to attend math lectures is to have already read the chapter in the textbook and attempted to understand it. That way, the lecture addresses the gaps in your knowledge and you can ask questions.
This time-intensive strategy might be suboptimal in the long run if it reduces the time available for doing homework / sample problems, which is almost certainly the most effective way to actually learn the material.
I had an otherwise excellent (if infamously uptight) calculus teacher in high school whose one mistake more than undid everything she did right: she insisted that everyone take extensive notes. She also moved quickly though materials and examples, making the problem worse. It ruined the class.
Also, at uni, I learned that taking notes in maths classes is a recipe for disaster. How come? The mere act of writing down and arranging formulas on my sheet takes enough thinking power that I can no longer follow the lecture. What's better, having one single good shot at understanding things, or having not understood things and the incomprehensible scribbling of your notes also makes zero sense without the professor's explanation? The former for me. As long as I know the broad subject names, I can read up on my own.