The key to memory is.... repetition. You never forget your name, your address, your parents names, your brothers/sister's because you are constantly bombarded, until they become etched into your memory.
I like to refer to memory as a well. If you hear something once, it just drops to the bottom, and pulling it out is very difficult. If you keep revising something consistenly and regularly, you ensure that the memory is 'imprinted' on the top layer of your memory (metaphorically) meaning that it is easily acessible, not just in the short term, but in the long term.
Revising work within 24 hours increases memory retention by 60%.
Revising doesnt just mean reading the work, you should be constantly asking questions and answering them (at least in your head) as well
Revising that same work, 2 /4/6/8 weeks later, will increase that memory retention to close to 100%, or permanent memory- great for the final exams, and for uni and life in general.
Notes aren't that important, what is important is constant revision, and making sure you know the syllabus and rubric.
What notes ARE good for, is making sure you've covered everything in the syllabus in a condensed and organised form. Notes in themselves won't do that much unless you revise them constantly and keep updating them- on a daily or weekly basis. Spending 20 hours compiling chem notes 2 weeks before your trials ISNT effective, at least compared to building the notes as you go, to increase, and constantly reinforce your level of understanding.