Start 10 days b4 boards , start with english.
Dont ignore jee completely, atleast devote 1 hr everyday
Do chem for mains with boards simultaneously.
A good method to study phy and chem would be to open the last page (index page) and start searching for words you wont be able to explain in deep.
Read those topics and you are done for most of the chapters which r common with JEE.
For maths u only need to see solved examples..i feel rest you might be able to manage.
Btw how much r u scoring in this mains?
@Supreeta_Sen can i get a little bit of background about you? Like how much syllabus u have covered and how much r u scoring in mains this time ..and r u done with Advanced only chapters like SOT and qualitative analysis?