Understand each and every concept thoroughly, revise and retain. Understand the importance of this by following example.
If I want to play badminton, the very first thing I need to do is to fetch a badminton racquet and a shuttle cock. This is equivalent to enrolling yourself into some institute or if you are preparing through Self Study then buying books.
Understanding the rules of the game is equivalent to understanding the concepts.
Now remember these rules so that you can use as and when needed.
Once revised then practice at least 30-40 questions on each subject every day. If you are watch your coach playing badminton for hours and hours, you will come to know about the rules. But tricks cannot be absorbed unless you play. In the same manner, if your teacher solves hundreds of questions on (Black/White) Board, you will only know the rule. To become master, you have to do these questions yourself.
In JEE Main, you will be given 30 questions in each subject to be answered in a time restriction of just 2 minutes per question, out of a total of on an average 25 chapters in each subject.
Just imagine, which questions a student would attempt during that time limit? The answer is only those kind, which he/she has done before. Something completely new coming your way, you would explore and kill time.
To avoid this, it is suggested that you must do each and every type of question ever possible on any concept.
Timely Doubt Clarification: Once you get some doubt(s), make sure that you clear the doubt(s) immediately without any delay.
Retention: Over these years of teaching, I have seen most of the students put complete efforts on developing on the chapter, which is going on in the class at present but when something related to things taught 1 or 2 months ago asked, they go blank.
Please do not let that happen. In that process the chapter we are working on at present will vanish after a month then why do it?
So, if doing, make sure that you fix one or two days in a week only for revision.
At the end of every chapter prepare some chapter-wise key notes, which contains all those points, tricks, concept we need to carry along. And Revise these Notes often.
Once you are done with a chapter complete all the exercises of NCERT for board examination preparation sand one source which is rich in questions for competition.
Just take care of these things and SUCCESS IS BOUND TO COME.