You are doing a right thing by writing online mocks ! that’s the best way to improve in anything.
Talking about study material,you should solve a book by R.S. Agarwal for this. Solving 2 hrs per day is more than enough. Solve all types of questions from the book, that would increase your problem solving ability.
Keep giving mocks regularly and analyse them. You wont be far from success soon! 🙂