When students enter in the class 11th then they have to study those topic which is in the syllabus of IIT-JEE. the best way is to study class 11 and IIT-JEE simultaneously . You should try to complete approximately 3 lessons of physics , chemistry and mathematics( one each) every 10 days.
that way you can complete 9 lessons a month but some lessons are very big so for easiness you can treat them as two chapters and schedule accordingly. if you study your 11th standard syllabus with IIT-JEE that will gives you a strong foundation for your board exams but always remember that your board exams are more important than IIT-JEE.
I recommend a three hour examination every two week with cumulative syllabus in first year to judge your preparation . this type of examination you can take with yourself or your coaching institute. your positive attitude towards examination from the day one will help you immensely . cooperate with your teacher they know the material , examination pattern lot and scheduling of learning seasons.
For better preparation of IIt-JEE you have to study minimum 10 hour a day. one can make individual judgement with the overall constraint that you have to reach a level of having the ability to write an examination in the material that you have studied.
In my blog i have post one article " How To Make Effective Notes" . Preparing a revision notes as you study is most important because that time spent by you in revising earlier lessons later on.