Hi Subir,

It is not necessary to take coaching to crack jee mains instead the main keys for cracking jee are self dedication and self control.

It is hard to score 99.98 percentile by self study but it is not impossible. To make a time table for your January attempt, you must go through the complete syllabus of jee main because it is different from advance and check how many questions are appearing from each topic in previous year papers.

Set your schedule according to topics with most importance. In my opinion, you must focus more on physics, then mathematics and last chemistry.

Also, find your strong points and keep strengthening them by regular mock tests and question solving.

This takes me to the point of which books are necessary for self study without any coaching material for specifically JEE Mains-

Physics- HC Verma (Vol.1 and 2)

Chemistry- Dr. O.P. Tandon

Mathematics- R.D. Sharma(Vol.1 and 2), Arihant Publications by SK Goyal and Amit Agarwal

But, keep in mind to solve the complete NCERT of physics and chemistry and solve MISCELLANEOUS exercise of maths NCERT.

You can also solve previous question papers of JEE by purchasing the following book-

Https://www.amazon.in/Chapterwise-Topicwise-Solved-2018-1979-Chemistry/dp/9313163306/ref=sr_1_3?crid=3B2CKLBDLBDRB&keywords=jee+previous+year+question+papers+solved&qid=1558699745&s=gateway&sprefix=jee+pre%2Caps%2C897&sr=8-3

It is competely your choice.

Make sure that you follow one book for each subject and solve it thoroughly.

Feel free to ask more queries.

All the best!!!