First of all, you must do extracurricular exercises. Basically, it is enough to fully understand the textbook. Make sure you finish reading a book every semester (in fact, every subject is very useful). If you feel relaxed in class, do something difficult. You'd better find a teacher to recommend this book.
Now in the summer vacation, if you study by yourself in advance, all the textbooks for next semester can be solved, because there are examples and after-school questions, and the difficulty is not very great. Every night is 1-2 hours (understand the content first, then do it, and repeat it the next day if you make a mistake, which will help improve your self-study ability and help you study later). That's what I did before. As a result, the math study next semester is very easy, and the big exams are basically. This method is very recommended, and my classmates do the same. I can finish reading a book in about a month.
Usually in class, I don't know what you are like In the past, our teacher only talked about four examples in one class, and everyone would take notes, but they should review after class, because what they understood in class would soon be forgotten and had to be done repeatedly.
Don't be discouraged even if your grades can't be improved immediately. At the beginning, everyone's grades will be around 70, but after repeated review, even if they reach the same level, they will basically get high marks. But we can't stop. It's a hard process anyway. It is certainly not wrong to do more problems in science. Personally, I think the method is different, and I will experience it slowly.
In addition, mathematics does not advocate rote learning. Do more basic publicity and you will naturally write it down. Questions can be classified appropriately. The topics of high school are diverse. It's normal to think of it once when you do the problem, and sometimes you will suddenly have inspiration. There are many such situations.
If you want to learn, that's fine. Come on!