Self-study is the key to success when it comes to preparing for competitive exams like JEE. You should make it a habit to study for at least 6 to 8 hours each day. Apart from textbooks, you should also read reference books, solve previous year question papers, and take mock tests.
For JEE preparation, there are a multitude of books and study materials available. You need to choose the right ones that are in sync with the syllabus and the level of the exam. Apart from textbooks, you can also refer to online study materials and video lectures to supplement your preparation.