Hello Aspirant, First of you need to focus on NCERT as it is very important for JEE Mains as well as for Advanced, but questions comes directly in JEE Main from NCERT.you should also take a print out of the JEE Main and JEE Advanced Syllabus as you should know that which topic comes in which Exam, for example - Chemistry in Every day Life is in the syllabus of JEE Mains but not in JEE Advanced. you should buy JEE Main and Advanced both previous year paper book so, you should know that which type of questions comes from which chapter.

Some of the books are

Physics

HC Verma is best, more over you can use some books for understanding theories.

Chemistry

MS Chouhan for Organic

Narendra Awasti for Physical Chemistry

For Inorganic you can use VK Jaishwal or other also

Mathematics

Arihant publications