The primary emphasis is to be on depth of knowledge, analytical and comprehension skills and attitude.
If you are a class 11th/12th student, try to synergise your school study with the JEE study. While doing a new topic, always do it first from your school textbook followed by higher level books.
Self Study Plan: School Students: A student going to the school should follow the 4/10 plan, that is self-study for at least 4 hrs. on school days and at least 10 hrs. on holidays. There must be a 7 day or 10 day revision plan as well. 12th Pass Students: A student not going to the school should follow the 10 hrs. plan, that is self-study for at least 10 hrs. everyday. There must be a 7 day or 10 day revision plan as well.
It is more important to do a question completely rather than trying to do more half-done questions.
Note that too much of test taking does not help. Only a deep understanding and other personal attributes can get you through JEE and not blind test taking. The frequency of test taking may be less for JEE 2007 aspirants in class 11th but needs to be higher when they reach class 12th.
Do approximations in calculations keeping an eye on the error.
In objective type of questions, method of elimination of options may work to your advantage in many questions. Using dimensional analysis, putting boundary conditions, putting values of variables, working backwards and many more techniques may work in such scenario.