1. Learn to say NO! Don't even bother with a "maybe". Every teenager knows that "maybe" essentially means "yes," especially if he or she's determined to get their way in the end. Despite the temptation to be your teen's best buddy, your primary responsibility is that of a parent.
Teens need you to set limits and establish rules, and they especially need your patience and persistence in helping them learn self-control. While kids with bad attitudes and rotten behavior might not be among tomorrow's leaders, it's OK to allow a little sass in the right situation. Just think of the successful lawyers and politicians who discovered their love of debate as teenagers trying to negotiate a later curfew or the keys to the family car on a Saturday night. So even though your teen might think you're being overly strict now, you'll both be happier in the long run.
2. Teenagers are like stubborn plants—they won't thrive without encouragement and occasional watering. Believe it or not, your words of support help to build confidence and self-esteem, which (hopefully) leads to stable relationships and successful careers down the road.
Encouragement can take many forms; a good grade on a test or paper can earn a simple hug or an elaborate celebratory meal. But if you can't get your kid to accept a hug without dramatic protests and lots of eye-rolling, you can at least try to embrace your kid's interests. So get involved and most importantly, try to set aside your prejudices. Even if you were rejected by the drama club in high school, it might be the perfect outlet for your teen's thespian leanings.
Remember parents: growing into an adult is a bit like riding a bike—you'll watch your child fall over and over until they get it right. Your encouragement in the face of frustration is just as important now as it was when they were a child. The problems may be bigger than the scraped knees of yesteryear (if your teen is clumsy, this may still be an issue), but with encouragement and positive reinforcement you might just make it to graduation.