Hi niketh . I am happy that you are planning to start you preparation for IIT. And it's a good time to start as you are in 11th. The timing and hours depends on your daily routine and interest. I was preparing for both engineering and medicine. I ll tell you what I personally feel good. If you make a entirely different schedule from what's being taught at school. It isn't going to help. I would advice you to try and make a schedule that would be in sync with your academic curriculum at school. So that you can dedicate time for both school exams and entrance efficiently. Even if you are dedicating a solid 1 hour with complete concentration. That's more than enough. But it depends on you. The way u read, your interests. An average of 1 to 2 hours with complete dedication is good enough. Listen to lectures in class , read the same topic in the evening , solve questions from that topic. Try solving as many as u can. The more u solve the merrier. But do remember to correct and analyse and rectify your mistakes. That's the vital part of learning. Not just solving. And after that you can take a break , relax and do your other homeworks too. Use your weekends to complete pending topics and revise whatever u learnt that week. The more u enforce a topic. It sticks better. Hope this helps. Good luck