To get into prestigious IIts, first and foremost your ranks should be under 10,000 and for that  ascore of above 210 is considered safe for entry into all the IIts with JEEadvanced.

To score big, we suggest you to devote atleast8 hours a day with weekends most focussed on mockexams for all the chapters you have studied.

You can take up AllenKota test series once you are fully prepared, once you're done you need to analyse your mock scores and areas of improvement and keep revising concepts and questions where you commit mistakes.

some top useful books helpful for top scores listed below:

Physics:- 

Concepts of Physics Vol I and II by H.C. Verma

New Pattern JEE Problems: Physics by DC Pandey.

Chmeistry:-

Organic Chemistry by O.P. Tandon

Numerical Chemistry by P.Bahadur

Mathematics:-

Maths XI & XII byR.D. Sharma

Kindly check below mentioned preparation tips as well:

https://engineering.careers360.com/articles/jee-advanced-preparation-tips-physics-chemistry-and-mathematics