I have a lot of opinions I want to just throw into the ether - no attacks on anybody, and I really want to start with this preface; everybody is different. People who get 50s aren't just people who did really well, or are really smart - the biggest thing that they achieved was finding a system that works for them. That doesn't mean it's built for everyone. So if I say something along the lines of, "you don't need to do this", and you did that and found it helpful, it's not a call out to say you're wrong - nor is it evidence that I'm wrong. It's evidence that you found something that works for you, and may not work for others.
The first one I want to call out - doing chapters early. Firstly, education research suggests that you learn material better if you take it in in 3 separate stages - once prior to learning it in class; then with help from the teacher and with structured, expert guidance; and then by revising the content a final time later. Most classes are actually structured this way, with most teachers using a "do now" at the start of class to get you thinking of the material, they will then teach it to you in a way that suits their pedagogy (way of teaching), and then assign questions as homework for you or gauge your learning using an exit ticket. But you can do this on your own as well - by reading textbook material before you learn it in class, trying some questions, then letting your teacher teach it to you, and finally revising in a manner that doesn't involve doing the questions - maybe you write notes, or answer different questions.
So, if that's true, why would I "call out" doing chapters early? Because if you do that prior reading, and it's too far removed from when your teacher covers it, then you defeat the point of the prior reading, and it's really important you use your teacher to cover misconceptions so that you aren't learning the material poorly - practice does not perfect; perfect practice makes perfect. Having said that, people in the past have found it good to do prior reading before the year - and then re-do that prior reading closer to the lesson.
The next one - question repetition. As above, perfect practice makes perfect - but that doesn't mean you need to do every question imaginable. In my own learning, for the entirety of circular functions graphing/algebra in methods, I did 3-4 questions per exercise. And I don't mean multi-part questions - for example, one exercise I did 1a, 1d, 2a, 2d, and that was it. But sometimes, I'd do every question - when I first learned integration of circular functions in spec, I always forgot to divide by the coefficient of the argument, so I did every question on it in the textbook until I could unlearn that bad behaviour. Do the amount of questions that are right for you, and do enough that you feel competent. Then, after the topic, go back, and see if you can get the basic questions correct again without revising the material - that way, you'll know for sure that whatever amount you did before was enough to get the information in your head.