Well, seeing your concern with JEE advanced 2020, it appears you are a drop out student.

With this one year, you have to prepare quite a vast syllabus and also have to hold an indepth knowledge. 

I would recommend you to join a coaching institute of decent reputation at your region. This will provide you all the necessary material, training and guidance you would require during your preparation.

If you work hard then one thing I can assure you, you'll never forget those late night homework completion, joince in solving alll the questions of the sheet, aksing doubts late after the class.  

For more references, go through my profile on Quora (user name - Arpit Agarwal)

All the best