IITJEE is the toughest engineering entrance exam in the country and the condition to qualify the exam is that you should be better than your competitors. This will need full commitment from you and you will have to eliminate most sources of wastiong time from your schedule. You must relax for short durations of 5 minutes for every hour of study and should try and study as much as possible in any day. That is the only secret to clearing IIT JEE.
Apart from this, joining a good coaching center, revising and re-revising your concepts, attempting and understanding difficult problems, solving test papers and learning from your mistakes regularly will boost up your chances of clearing IIT JEE.
Kishan S Srinivas