Hello

Your NCERT Chemistry textbooks for Class XI and XII  is really good for jee mains,

you should go through the chapter well first and then go through  all the solved examples, intext questions and exercise questions .

Now , your whole chemistry is divided into three parts physical chemistry ,organic chemistry and Inorganic Chemistry

For physical chemistry first of all go through the chapter then make a list of all the formulas and important concepts in the chapter then go through the solved numericals to understand how the concepts learnt are applied to solve them and then go for unsolved questions

In inorganic chemistry, you basically have to  memorize things, show the best thing is read the chapter from NCERT and keep revising it at regular intervals , and practice lots of MCQs to increase your memory power after each chapter

For organic chemistry ,  you don't need to directly mug up reaction to first understand them, what you need to do is first go through the reaction and then go through it mechanism as well which will help you to understand how the reaction proceeds and then write two- three times the reaction and its mechanism on your own and then practice some questions on the same reaction and you need to follow this process for every reaction in organic and soon you will be good at organic.

And finally after completing the NCERT go through previous year questions of JEE mains and sample papers as well

Thankyou