You are a student of class 9th.can any one tell you how to study mathsphysicschemistrybio.as your big brother is not happy with way studing?

Hey, I'm struggling a bit with Math, Physics, Chemistry, and Biology. My brother says I'm not studying the right way, but he doesn't really explain *how* to study better. Can someone give me some tips? I'm in 9th grade, so I need advice that works for someone my age. I'm really trying to improve!