This is because you don't create interest and passion in you to know physics. Take this subject as your everyday task because physics is what we see everyday. In every work, physics is involved.
We must know applications of the chapter or topic before studying it. This will create interest in you. Relating your study with reality will make it enjoyable.
Like before studying rotational motion which is very important for JEE, explore about its engineering applications. If you do this for every topic, it will be perfect.
Never use formulas directly in numericals . Before applying them, think about from where it is derived. Start from basics and try to use basic concepts to solve problems instead of directly using bookish approach. Try to solve problems in 3-4 ways. Brainstorm with problems instead of accepting the standard solution given in book or prescribed by your coaching mentor.
In physics, never ignore your doubts. Clear them as soon as possible.