Create an everyday / weekly to do list and follow according to that.
Complete your class 11th syllabus till December, twice and class 12th syllabus by March,twice.
Give mocks every week/ fortnights. Analyse where you went wrong and correct them. You can buy a test series. Solve PYQS at least twice. Always always questions with time.
Sundays should be for test or revision of everything that you have studied the whole week.
Create formula notebook for physics.
Write all the reaction mechanisms in organic chemistry in a notebook.
Read NCERT bio 15 times and solve NCERT phy, chem twice.
If time permits, solve pyqs of JEE. Last 5 years would do.
This alone will fetch you 650+ marks.