One thing I've learn is that with independence comes responsibility.
High school students can count on parents and teachers to remind them of important responsibilities that must be managed. They are there to help guide them in setting priorities and schedule management. In college, all that changes. It is becomes the duty of the student to balance her responsibilities and set her own priorities. For example, no one will tell me to study for my upcoming exam; I will be the only one who is going to push myself to take and manage my responsibilities. These responsibilities also include developing the self-discipline to study these difficult academic subjects.
Naturally, academics constitute a major difference (an upgrade) between the high school and college levels. Not only does the academic difficulty change, but also the scheduling structure is more relaxed; it provides for more freedom and flexibility. In high school, each day students proceed directly from one class to another. By contrast, in college, students make their own schedule, often leaving hours and hours in between classes with class times varying throughout the day and evening. Also of importance is the increase in the personal homework. It is normal for high school students to spend five to ten hours per week studying outside of class. That's five to ten hours total. In college, however, it is often necessary to spend at least three to four hours studying outside of class per every hour spent in class. That is a dramatic increase! Imagine, for the average student who has five classes, that equals approximately 40 hours of homework per week. Compared to high school, college is no minor step upward.
Another difference between college and high school is the contact that students have with their professors. In high school, the contact is special. In college, professors cannot and do not give their students all of their attention.