2, notes: as far as possible, notes do not refer to the original blackboard, boring, and do not need to use a small notebook alone, you can write it down in the notebook. The key is to have your own summary of each chapter in your notes, similar to an outline (sometimes in a teacher or reference book, you can refer to it), and it is best to have various questions+methods+error-prone points.
3, class: it is recommended to listen after previewing. It doesn't matter if you don't understand. Many college courses are reread after class in combination with teachers' notes. But remember, don't make a surprise attack before the exam, it is absolutely impossible. You should keep up with it at ordinary times and try not to make mistakes step by step.
4, learn high number = basic concept+basic theorem+basic network+basic knowledge+basic question type. Mathematics is a concept+theorem system (and reasoning), and it is very important to understand concepts, such as limit and derivative. We should not only understand them vividly, but also remember their mathematical descriptions. Instead of rote learning, it is better to give examples to the book, draw a picture (image understanding is actually very important), and then do more questions and experience. It is suggested to mark all the concepts with colored pens, so that when reading a book, it is clear at a glance (the theorem has a box).