Studying Math is Different from Studying Other Subjects
Math is understandable by doing problems. Do the homework regularly.
The problems help you learn the formulas and techniques you do need to know.
Each class builds on the previous ones. You must keep up with the Teacher: attend class, read the text and do homework every day. Falling a day behind puts you at a disadvantage. Falling a week behind puts you in deep trouble. You're always reviewing previous material as you do new material. Many of the ideas hang together.
Identifying and learning the key concepts means you don't have to memorize as much. Do not hesitate in asking question. Practice as many questions as you can.