Routines play a major role in successful study skills. The ability to keep a consistent schedule will make studying consistent and in turn learning will become consistent.
To maximize your study time, set up your own routine and follow it closely. Perhaps the first couple of hours after school are dedicated to extracurricular activities. And then dinner might follow.
After dinner, set up one to two hours of solid study time. Don't deviate. Dedicate the time needed to learn new material, prepare for exams or complete assignments. Even if you think you don't have anything to do you can always use that time to get ahead and learn more about a particular subject.
After a solid block of study time, have some time to relax. Watch some TV, play games, chat with friends or do something to refresh the brain. If you need to do more studying, take another block of time and focus on your studies.
Once you have a set routine you can always adjust. In fact, the beauty of a routine is that once you have it established you can learn that some activities might require more time and some might require less.
In all, one of the most important lessons learned in school is time management. Setting a routine will help you manage your time so you can maximize your study hours.
And if you don't set a routine, you might get lost and overwhelmed with outside influences that do not contribute to your academic learning. A routine may be boring, but they do work.