Establish study time, homework time, program time, and free time. Limit the use of the television, stereo, and telephone. When establishing a structure, be firm but reasonable. The first thing to schedule, not the last, is free time. You cannot expect a child to spend six hours in school, come home to homework and program, then go to bed so that they can get up the next morning smiling and eager to begin a new exciting day.
Time needs to exist each day in which the child can be a child, to relax and have fun.
If you create a negative environment, do not expect a positive child. Working with a teenager requires a terrific sense of balance knowing when to pull back on the reins, and when to let them have their head. Do not be afraid to establish structure. The nature of the beast is such that they resist structure, but really welcome it. Teenagers are at a point in their lives where hundreds, if not thousands, of options open up to them.