Generally speaking, learning math well is very tiring. First of all, you must listen carefully in class and answer questions actively (no matter how much you know, how much you know). In this way, the teacher can know your mastery at the first time, help you solve your doubts and make it easier for him to prepare lessons next time. Ask teachers and classmates in time if you don't understand. Write down the topics that are often wrong or that you think are more important (that is, your own difficulties and mistakes) in your notebook, and take them out when you have time to review and learn new things. Summarize every exam and review in time when you find your own shortcomings. I hope these are useful to you.