Be curious rather than judgmental.
If you remember and apply this mantra regularly and consistently, you will be halfway there in improving relations with your teen.
Much negative behavior is driven by a need for attention or a need that isn’t being met. Responding with force or ultimatum reinforces negativity and invites resistance.

The new sex education requirement for all students in public middle and high schools is “long overdue,” writes the The New York Times (August 10, 2011). The sex education push is part of an initiative by Mayor Michael Bloomberg to address the needs of young people in minority neighborhoods, where blacks and Latinos are most affected by the consequences of early sexual behavior and unprotected sex.
Starting in 1991, Dr. Jay Giedd, chief of brain imaging at the Child Psychiatry Branch of the National Institute of Mental Health, starting taking pictures of children’s brains over a period of nine years, using magnetic resonance imaging (MRI). He and his colleagues studied some 1,000 healthy kids (including two of his own) at intervals ranging from two weeks to four years.
The more respected your teens feel, the more open they will be with you. The more power you share with them (without abdicating your role as a parent), the more trusted they will feel and in time, the more cooperative.
There is no need to cheer, clap and comment on everything your child does. When we consistently rescue, fix and overprotect our children, we rob them of the opportunity to learn from their mistakes, as well as to know that they can survive disappointment.
“Encourage the deed [or effort], not the doer.” — Rudolf Dreikurs, psychiatrist/educator, (1897-1972)