Certain key things have to be remembered when preparing for the IIT-JEE exam (or any other competitive exam for that matter)
MOTIVATION: What is it that is motivating you to write this exam:
a) A good career ?
b) Parents’ pressure ?
c) You don’t have anything else to do...
It is very important to be clear about the factors that are motivating you. If it is mainly external factors such as parents forcing you to do it, then you have a problem in your very first hurdle. Always be clear about what benefits you derive from clearing the exam and how  useful it will be to you.
The feeling of success should be able to thrill you, to fill you with enthusiasm.. not make you feel relieved that your parents won’t force you for sometime now.
Once you get your source of motivation right, it’s only a question about playing it back again and again frequently in your head. The main purpose of this being to ensure that you don’t lose track of your goal
PLANNING:  It is very important to be a frequent planner. It is vital that planning to study be done by you alone because you are the best person to know about your strengths and weaknesses. Have a long term plan and a daily plan in correspondence to the long term plan..
For instance a long term plan would be to finish Calculus in the next two months.. while a short term plan would involve doing a particular exercise in the Integral Calculus chapter.
However, note that it is impossible to do 100 per cent of what you have planned. Even if you come close to 60 per cent, you are on the right path I would say.
FEEDBACK: The importance of feedback is realised when one sees improvements as a result of the feedback. Feedback is an important way of knowing whether your methodology is working or not. Feedback can be in the form of your All India Mock Tests Ranking or your test scores in a particular subject or plain simple verbal suggestions from your teachers or the best of them all, your own self.
PEERS: It would be immensely helpful if some of your peers have the same ambition as you. It is a good way to set up a competitive spirit and keep a look out for one another and ensure that no one burns out.
FUN: One thing can be said for sure and that is "if you are not having fun while preparing for your exam, then it will be an added obstacle which you could have done without".
The fun factor is always under emphasised but I think it is the most important of all the tips one can get. Fun is a great way to prevent burn out, to rejuvenate oneself.
Bharat K