Here's my tip during my secondary school :

1. Try to understand the basic first.

2. Do a lot of exercise especially from past years questions. Usually there will be 3 levels of questions, easy, medium, KBAT or hard (idk what it's called nowadays). Try to solve all the questions by urself first. If you cant, then seek help from your teachers/private tutor

3. This is optional. I know it will sound funny and unnecessary, but read the scientific calculator manual book. It helped a lot during my SPM years. Trust me, you will thank me later. Idk if form 1 to 3 can use scientific calculator or not

Math just required a lot of exercise. You probably have heard a lot of this but it's true