There is no best way known. That would be a way which enables one to score 100% in both JEE(Main) and JEE(Advanced).

But still, what you must ensure is that by the time of your exam, you know each and every concept well. And the most important thing is to have faith in yourself. I used to believe in myself in every exam, and it turned out well in most cases.

I won't recommend books or coaching classes, I would just say that study for fun, and make sure you know as much as possible before you attempt any exam. And then give it with your full energy.

'You only get one shot, do not miss your chance to blow, this opportunity comes once in a lifetime, yo!!!'

-Marshall Mathers III

You can also check out this app I made for helping JEE/NEET/Olympiad/KVPY/NTSE aspirants with courses, notes, blogs, and much more- AcadBoost