Hello Bhaskar Biswas,

I would like to tell you some tips for JEE MAINS below from careers360's:

• Finish the Existing topic and then move ahead-An essential aspect of the JEE Main 2019 preparation tip is to first finish some of the basic topics and be very thorough with them before you proceed further. 
• Develop clarity of concepts- One of the important JEE Main preparation tips is to grasp the concepts well. 
• Prepare short notes or flashcards- During the last stage of the preparation of JEE Main, candidates cannot afford to study the complete books. It is then that these flashcards and short notes prove to be very handy as you can go through them very fast and recall the important points.
• Practice the JEE Main Sample Papers and Question Papers- One of the pivotal JEE Main 2019 preparation tips include solving of the sample papers and the question papers. The aim to solve the question papers is to enable you to know the level of their preparation. 
• Mock Tests- Taking of the mock test at a time when the actual exam takes place is also part of JEE Main preparation tips.
• Revision- JEE Main 2019 preparation tips also include revising thoroughly what all you have studied.

I would suggest you visit the careers360's link given below which has detailed info of the tips and weights of chapters for JEE MAINS.

The link for the same is:https://engineering.careers360.com/articles/jee-main-preparation-tips

Hope this helps and all the best!