Dear Daljeet,
For IIT JEE preparation .. the first very important thing is clear and enhance your concepts .. jus keep this thing in mind that building concepts and practicing a lot is damn important for IIT preparation..
Always start from BASICS because "without base, there will be no altitude… Never prefer solutions of questions before doing SELF-ATTEMPT at least five times till you get the right answer because "without fall you can not stand at once".
Study without loosing the concentration coz studying 2 hours with very good concentration is equals to studying 5-12 hours without any concentration. . and have a confidence in yourself.
Please feel free to post as many doubts on our disucssion forum as you can. If you find any question difficult to understand - post it here and we will get you the answer and detailed solution very quickly. We are all IITians and here to help you in your IIT JEE preparation.