I am in class 12th and my dream is to get top JEE IIT what strategy I need to do for best preparation?

You need to work hard if you want to crack this exam. Be consistent & focused. Work on weak areas & strengthen strong areas, take mock tests regularly

First, make a good time table to follow. Be motivated and self determined. Chemistry is one such subject which can assure you guaranteed marks in IIT JEE if you have prepared well. Most of the topics in chemistry are not very much twisted and get tested directly. It is very much advisable to solve past 20 years(Minimum) IIT JEE papers for chemistry. Most of the questions are repeated in an indirect manner. This is true for inorganic and organic chemistry than physical chemistry because in physical chemistry lot of concept testing is involved. You can solve previous year papers to know the exam pattern. You can also solve complete mock test twice or thrice a week to judge your performance and to know your strength and weakness