I have a similar experience with you. I am poor at math in junior high school, and I will fail. I just graduated from high school and did well in math. I can give you some advice. You should prepare two notebooks, one to take notes with the teacher in class, that is, to remember some knowledge points, and the other to sort out typical examples, not to sort out all the questions, but to sort out some typical types, so that you can draw inferences. Then, homework is very important, and homework after class must not be sloppy. I have copied my homework for a while before, and my grades have fallen sharply. I must think carefully by myself. If you can't, you must ask, don't ask the answer, but understand the train of thought, so that this type of problem will be solved in the future. Mathematics in high school is mostly the foundation, so it is very important to lay a good foundation. As for some difficult problems, not everyone will know, but it is up to these problems to widen the gap. I suggest that you specialize in difficult problems after the basics are ok, and don't write difficult problems as soon as you get them. If you do more difficult problems in high school, you will find that they are almost the same. It is important to summarize the methods and ideas. The most important point is calculation. There are many calculations in high school, but you can't use calculators in the college entrance examination. You must calculate well at ordinary times and don't be lazy. No matter how difficult it is, it will count, otherwise the exam will not count! I know this well, senior!
Pure hand tour, hope to adopt! Senior sister's advice should be effective, stick to it!