While the recommendations that I am about to make to you are no guarantee of success, I believe they will optimize your chances of success. The average person will study four hours for a daily quiz, four hours for a weekly quiz, four hours for a major test, four hours for a midterm, and four hours for a comprehensive final. The outcome of this four hours of study will vary from an A for a daily quiz to an F for the comprehensive final. This means that in high school grades are strongly determined by intelligence since everyone studies the same amount of time.
College is different.
Most of the students are highly intelligent and some are highly motivated. In almost all college courses if you have a poor vocabulary and do not really like to read, you are in serious trouble. If you can succeed with your weird teachers, then you can succeed with your even weirder bosses. Your study habits formed in high school may vector you toward failure because you have never experienced what it takes to perform at the college level. That is why the freshman year is the hardest year you will ever experience in college.