First, if you need to actually memorise something (rather than just understand it and pull it out of your head) try
Anki, this awesome spaced repetition software that doesn't let you forget. Have to use it daily though.
Passively reading notes is essentially useless - it doesn't stick. It's like eating those big brightly coloured multivitamin tablets - if you don't chew them, they kinda come out the other end just as big and just as brightly coloured
You haven't actually absorbed any of the nutrients because you haven't actively digested them.
I'd recommend using multiple sources and combining to make your own notes - often state rank notes have left out bits that they already knew so they miss bits, awesome as they are. Also, if you reorder and write in your own words, this makes you process the information.
The key thing though is to constantly TEST yourself - so yes, prac questions are great, but also after you've read a section of the text, you should test yourself on it - close the book and try to summarise in your own words what you read; ask a question about the content and then try to answer it without the notes. Active recall is far and away better than passively reading, where it goes in one eye and out the other.
As mentioned above, actually
understanding what's going on and why takes away the need to rote-memorise long meaningless formulas, because you can figure it out on the spot and why without having to have memorised it.