Which are the most useful books for JEE mains in Physics , Chemistry and Maths? .

I would suggest you to go through the below preparation points as these will be helping you -
1. Know your Syllabus Well.
2. Work on a Time Table.
3. Make your Basic Concepts Strong.
4. Improve your Weak Points.
5. Write Notes and Prepare Flash Cards.
6. Attempt Mock Test and Solve Sample Papers.
7. Revision.
8. Make Sure to Take Breaks.
9. Check out Proper Books for Preparation.

Books which you can consider -
Physics
Concepts of Physics Vol I and II by H.C. Verma
Problems in General Physics by I.E. Irodov
Fundamentals of Physics by Halliday, Resnick & Walker

Chemistry
Numerical Chemistry by P. Bahadur
Organic Chemistry by Paula Bruice Yurkanis
Inorganic Chemistry by J.D. Lee
Organic Chemistry by Morrison & Boyd

Mathematics
Maths XI & XII by NCERT
Trigonometry by S. L. Loney
Co-ordinate Geometry by S. L. Loney
Higher Algebra by Hall & Knight
Problems in Calculus of One Variable by I.A. Maron

Hope this helps!!!!

Below are the recommended books for your preparation

Physics

Concepts of Physics (Part I and II)- HC Verma

IIT JEE Physics- DC Pandey

Problems in General Physics- I.E. Irodov

Physics for IIT-JEE- Resnick, Halliday, Walker

Problems in Physics- S.S. Krotov

Chemistry

Organic Chemistry- Morrison Boyd, O.P Tandon

Modern Approach to Chemical Calculations- R.C. Mukherjee

Numerical Chemistry- P. Bahadur

Concise Inorganic Chemistry- J.D. Lee

Mathematics

IIT Mathematics- M.L. Khanna

Differential Calculus- A Das Gupta

Class XI & XII Mathematics- R.D. Sharma

Trigonometry, Geometry Books- S.L. Loney

Problems in Calculus of One Variable- I.A. Maron

Higher Algebra- Hall and Knight

Good Luck!!

Firstly I would suggest you to go through well with NCERT books properly to build your concept then prefer other books. the books you can prefer:

Physics : Concept of Physics by H.C. Verma , Fundamentals of Physics by DC Pandey , Problems in Physics by I.E. Irodov

Chemistry : Numerical problems in Chemistry by P. Bahadur, Organic Chemistry by O.P. Tandon.

Mathematics : Mathematics by R.D. Sharma, Algebra by Hall & Knight