Study regularly for two years, and you will get admission into an IIT easily.

Seriously, this is the thing that seperates the grain from the chaff when it comes to such a tough exam. Regular effort. Most people burn out too soon, and then study only when the exam is approaching soon. But you have time, and if you use it wisely, there's nothin in your way.

1. Join a good coaching institute/tuitions. This will help you immensely.

2. Find the right books for you. And follow those books instead of jumping from book to book.

3. Again, study regularly, and you'll never feel stressed out.

4. IITs are not the only option, remember that. 

Dear Ashish,

If you are interested in joining IITs you have to appear for JEE Advanced exam. In order to be eligible for JEE Advanced you have to qualify for JEE Main exam. 

In order to be eligible you should have completed your 12th class or you should be appearing and make sure you get 75% marks in your boards exam or you should be in top 20 percentile in general category.

For SC/ST it is 65% marks.

To take admission in IITs it is a dream of many students so competition level is very high. You should be determined and self motivated to crack your exam. 

You have enough time to prepare for your exam. Syllabus is based on 11th and 12th class only so make your base strong. Your concepts should be strong it will help you to get good marks in your exam. NCERT books are very important make sure go through it.

Good Luck!!