Dear aspirant,

I have a few tips for you to manage everything together.

First of all, make a schedule for yourself.  Set a target based on how much time you have. Make sure you finish the school portions everyday along with the class. There is not a lot of conceptual differences in what you'll have to study. So please pay attention in school and coaching. Set aside an hour everyday to revise through the concepts taught in school and coaching that day. Devote most of your self-study time to practice and solve questions. Amidst all this make sure you spend sometime playing/exercising/pursuing your hobby as well. For materials, I would recommend yout o get standard textbooks like OP Tandon for Organic chemistry, NCERT for inorganic chemistry, P Bahadur for physical chemistry, Cengage for Math and physics. But, refer only to one set of books, don't get too many books. Just, religiously stick to one book that makes you feel comfortable with the concepts. Practice previous year questions regularly. Based on what you have completed write mock tests atleast twice every month. In class 11 focus only on getting the concepts right as you don't have board exams to worry about. In class 12, spend 2-3 hours a week practicing board exam questions.

Hope this helps.