Hello Arvind,

There are various institutes offers crash course, You can join to do research before joining it. You can follow the tips given below.

In order to crack JEE Main exam make sure your concepts are clear. Your fundamentals should be strong. You can take help of NCERT books for that. Complete your syllabus first you can focus on important topics. You can solve MCQs related to important topics for your practice. You can refer previous year papers to understand the exam pattern and level of questions.

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The best crash course would be using toppr or byjus .

All the concepts are covered in it .

You should revise it. These online learning platform have good questions so try to solve problems topicwise .Smart work is essential .

Also mypat is good it has so many questions .

If you want offline 

Then resonance crash course is good