It definitely depends on ur time management and hours of full concentration ,next comes routine—don’t go to complete a specific subject first,divide your study hours among the 3 subjects —according to me—2 hrs for chemistry,3 hrs for math and 2.5 hrs for physics .Just choose a specific book for each subject and the subcategories and complete the whole book,choose relevant chapters ,i would suggest to follow the index lineup of the ncert textbook for each subject ,also make short notes in small notebooks and try to read them, every night just before closing ur eyes, on bed.

In case of math,u should 1st read the class 11th syllabus and then go for 12th one this will clear your concepts besides making u stronger in the solving tactics required for 12th,

physics is totally ur choice from where to start and chemistry—means 3 parts —Organic , Physical , Inorganic.For physical chem —read more and more the class notes ,reference books and solve them.Inorganic chem requires reading ncert textbook (also read the notes u prepare before sleeping everyday and solving the different objective problem In case of Organic chem the same and best option for reading will be ncert text book —in case of organic chem u should complete 1st the 11th syllabus followed by 12th one.

The best thing to survive in the long competition is to attempt a jee mains mock test every weekend for the chapters u learned in the present and have learned in the past weeks to know where r u lagging in the concerned syllabus.

PREPARE WELL —BEST OF LUCK