• First you need to download the IIT-JEE examination syllabus.
• Go through with that thoroughly such that you may can able to understand the weightage of several topics.
• From Class 9th onwards start preparing your basic concepts good such that from in IIT-JEE you can easily attempt more no of questions.
• Follow the strict routine time table having proper time for each and every particular subject as well regularly play any sport during the evening time for 1 - 2 hour.
• At last believe on yourself and don't divert your mind from the IIT-JEE preparation.

Hi

I would suggest you to focus on your present syllabus of class IX and make your basics clear and foundation strong. This will help you in your upcoming years. Keep your concepts in Physics, Chemistry and Mathematics clear from the very beginning. 

Hope this helps!

All the best!