I think senior one should first make sure that he is proficient in the knowledge in the classroom, strive to get full marks in every math exam, and try to learn new knowledge and related competition books by himself when he has spare time. Recommend the Olympic Mathematics published by East China Normal University and the competition book published by Zhejiang University, and insist on proper exercise every day. Senior one should not be underestimated, because the math league exam is coming at the beginning of senior three, so I suggest that I study the knowledge of senior two and senior three independently as much as possible in senior one, and choose to make competition books with corresponding difficulties according to my math ability. If you think your ability is not bad, I suggest that you can sign up for the math league in the first year of high school, and maybe get an award. This is very possible and can help you get familiar with the exam atmosphere in advance.
Senior two is undoubtedly the most important year. According to my experience, the focus of senior three last semester was to read enough competition books, accumulate skills and knowledge of competition questions, and rationally plan daily or weekly training questions, but remember to read as many competition books as possible. I suggest that the focus of this issue should be inequality, sequence and plane geometry. The main purpose of senior two is to do a lot of exercises and study algebra and combination knowledge in depth. During this period, there will be a set of test questions and several major problems such as inequality, sequence and plane geometry training every day. It is recommended to do the questions at night. During the day, I suggest reading more books about algebra and combination on the basis of ensuring classroom study. When you feel that your skills are enough, try to do algebra combination training questions with corresponding difficulty. At the end of the second year of senior high school, I suggest doing the test paper sets and simulated training questions in previous years, with the aim of training and improving my speed in doing the questions.
Finally, I returned to the reading stage at the beginning of the summer vacation of senior two and senior three. The purpose is to recall the knowledge and skills you have learned and summarize them. At the same time, you need to look at your previous wrong questions and classic problem-solving methods. It is best to know what method to use when you see the questions, and you may even see the answers directly. I think reading a lot of competition books is the magic weapon to win. I hope you can pay attention to it.
The above suggestions are all my personal experiences and thoughts, and I hope I can help you.
Finally, I wish you progress in your study and realize your dream as soon as possible ~