IIT JEE is one of the competitive level exam and it's a dream of many students to get into IITs.

In order to crack IITs it doesn't matter how many number of hours you are studying it totally depends on how much quality time you are giving to your study. 

Try to give dedicately 6-8 hours towards your study. 

In order to crack your exam make sure your concepts are clear you can take help of NCERT books for that.

Try to solve as many as many as mock test series and refer previous year papers for your practice.

All the Best!!