Read NCERT textbooks of 11th and 12th standard of Physics, Chemistry and Mathematics. 

Solve Multiple Choice Questions of each chapter after you finish it. Give equal attention to every subject as they are all equally important.

Make notes of formulas so that you can revise it before exams. For physics understand the concepts then solve numericals based on it. There are many reactions in chemistry so write them everyday so that you can remember it well. 

There are many good reference books available. You can refer them too.

If you still have any queries feel free to ask in the comment section down below. 

hello shivan sravan,

i suggest you to go through the given links,

https://engineering.careers360.com/articles/top-5-tips-to-crack-jee-main

https://engineering.careers360.com/articles/how-crack-jee-main-2019

all the best!

note: if any links available please copy then paste it in the address bar of your browser.

I Hope this information will be useful to you.

if you need additional information,let us know to help you.

Thank you!!!:)