One question that students have is about books they must study from, for JEE preparation. It is important to study from NCERT to understand theory and clear basics. After studying a topic, solve MCQs on them from books that have MCQs. For mathematics you can go for Arihant Skills in mathematics, A Das Gupta; for Physics you can refer HC Verma, and Irodov; for Chemistry use Paula Bruice, Solomons, JD Lee, Bruce Mahan, Vogel, Peter Sykes, Olympiad papers.

If you have study material from a coaching center you can solve questions from there also. It is advisable to solve previous years papers also.