Hello Aspirant,

See there are total 23 IITs in India which itself are the most prestigious engineering institutions of India but among them also there are some best IITs such as IIT Madras, IIT Bombay, IIT Kharagpur and so on. Now to get into such IITs for B.Tech course (if you want to ask about any other course offered by IITs, then please mention it.) you need to have good rank around in top 200 in JEE-Advance and to be eligible to appear in JEE-Advance you should clear the JEE-Main at least with the qualifying cut-off of JEE-Main of that year. To secure such rank in JEE-Advance one should follow the right and smart track of preparation because only hard work will not work in the huge competition of today's life. So I am enlisting down some smart preparation tips which will help you in your preparation of JEE-Advance so that you can get into the best IITs of India :-

• Very first thing is go through the syllabus of JEE-Advance and categorize it as easy, average and difficult. https://engineering.careers360.com/articles/jee-advanced-syllabus
• Make a proper time-table to balance your studies and daily routine work (like your hobbies, refreshing your mind and so on)  and give little more time to studies.
• Go for the best study material which can make you more confident while solving the question of JEE-Advance because it will boost your moral so in the last of this answer I will give you the list of some best books for JEE-Advance.
• Don't forget to make notes while studying because it will help you in memorizing the important things in the last time prior to exam.
• Practice previous year's question papers and sample papers along with different mock tests as many as you can because it will enhance your self-confidence and time management skill. https://engineering.careers360.com/articles/jee-advanced-question-papers & https://engineering.careers360.com/articles/jee-advanced-mock-test
• Don't forget to do exercise and yoga regularly to keep your body mentally and physically fit.

Some best books for JEE-Advance :-

@Physics

Concepts of Physics by H C Verma (Vol-1 and Vol-2)

Fundamentals of Physics by David Halliday/Resnick/Walker

IIT JEE Physics by Arihant (35 years Chapterwise Solved Papers 2013-1979)

@Mathematics

Objective Mathematics By R.D. Sharma

Plane Trigonometry and Coordinate Geometry (Two Books) by S.L Loney

Problems in Calculus Of One Variable by I.A.Maron

Integral Calculus for IIT-JEE by Amit M Agarwal (Arihant Publications)

A Text Book of Algebra For JEE Main & Advanced by Dr. SK Goyal (Arihant Publications)

@Chemistry

Physical Chemistry by OP Tandon

Modern Approach to Chemical Calculations by R.C. Mukherjee

Organic Chemistry by O.P. Tandon

Organic Chemistry by Paula Bruice Yurkanis

Organic Chemistry by Morrison & Boyd

Inorganic Chemistry by J.D Lee

Inorganic Chemistry by O P Tandon

You can check out the link given below for best preparation tips :-

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

I hope this information helps you.

Good Luck!!