Try to pay attention in your coaching classes or consult some professional. Also try seeing YouTube videos of PhysicsWallah... He explains greatly and in depth - all the concepts of PHYSICS. and once you are done with the theory of physics, start from little mcq books like Target and Marvel and then go on to solve ERRORLESS, universal self scorer and then if you have time and only if you are able to, solve books like HC VERMA, DC pandey OR IRODOV.

Thank you.