While preparing for entrance exams, you should use NCERT books first, as they cover all the basics clearly. For practice and deeper understanding, use books like HC Verma for Physics, RD Sharma for Maths, and MS Chauhan for Chemistry. For competitive exams like JEE or NEET, refer to books like Arihant and MTG series. Solve previous year papers and mock tests regularly. Stick to a few good books instead of too many to avoid confusion. Stay consistent and focused.