Buy the book linked below. Read it and follow the focused studying and calendar method.
My son was captain of the soccer team, a high level competitive skier, conservatory level musician and he was also a regular kid. He finished HS with all As and was never up studying later than 10:30 after he read it.
More importantly he finished his BS/MS in ME magma cum laude at a school that graduated a 4.0 once a decade while working 12-20 hours a week on campus.
It’s all about efficiency and organization.
How to Become a Straight-A Student: The Unconventional Strategies Real College Students Use to Score High While Studying Less https://a.co/d/fbu2L0K