Study regularly, find the right books (there are many lists available online), and the most important, stay self-disciplined.

If you do join a coaching centre, always stay levelled with what is being taught. Don't fall behind, hoping you can catch up later.

Always study the topics from a book as well, to get the best out of self-study.

U have to prepare from the start .
For IIT, you have to attempt and clear the IIT JEE MAINS.
the Scoring for IIT is above 90%.
U need to Prepare yourself and ready by the end if the year.

Thanks,
Azim