Hey aspirant, For scoring 90% and above in class 12th in non medical field you need to study hard as science is expected to be the tough of all and so is maths. Your 3 main subjects which are Physics ,chemistry and maths go hand in hand. If you have command on maths then it would surely enhance your physics and If you have the reasoning skills in physics then that would result in your strong chemistry. So all you need to do is need to study really hard and clear all the concept.

Hope this helps

Good luck