JEE exam preparation needs a good strategy :-

1. Good books/material:-

for physics- H C VERMA(for both theory/concepts and problems)

for maths- M L KHANNA

for chemistry- physical and inorganic- O P TANDON

organic- SOLOMONS

Take these above all books for making basics clear at first then see NCERT BOOKS and simultaneously mark the topics that you covered through these books and  read NCERT books only at last two months.

After clearing basics you need to take a latest coaching material to solve latest problems in JEE exam ,best material is from "allen/fiitjee study material". I am not promoting anyone just i have experience of many coaching materials.

2. Time management:-

Many students waste their time at schools classes ,see you cant take so much leave to do self study but you can do one thing ,you should take problem sheets with you at school and can solve them in free time and also ask doubts from school teachers and your friends.

Awake early in morning like 7:30 am and sleep at 12:30pm and can take sleep of 1 hr 30 mins at around 4:30pm.

3. Choosing most interest topics:-

choose topics with your more interest and make them strong first.

4. Set daily targets :-

set your daily goals but never demotivate if you fails.

5. always be self motivated

6. Never feel jealousy with your competitors