Teach your teen to: Speak for herself.
Why it works: "The more assertive a kid is, the less likely she is to be victimized or pressured," Borba says. Putting yourself out there, like any other human behavior, is a habit that can be learned through repetition. As often as possible, encourage kids to speak -- politely but firmly -- on their own behalf, ordering for themselves at restaurants, for example, or asking salespeople direct questions.
Teach your teen to: Use body language.
Why it works: "If your son holds his head up high and makes eye contact, it makes his 'no' mean more," says Borba. When watching TV with teens, point out characters who look strong and move assertively, and those who seem weak and unable to protect themselves, so kids can actually see what you mean when you talk about body language.
Teach your teen to: Repeat his "no" messages.
Why it works: Tell your son that when he wants to decline something he should pick a strong, clear line and stick with it. If he is offered a cigarette, for example, he should say, "I don't want to." If the other person keeps coming at him, he should just continue saying "I don't want to" for as long as it takes to get off the hook. Experts call this the Broken Record Technique. "The more a kid says no, the more he feels it and means it," says Borba. Staying on message will probably wear out the other person -- and build your teen's resiliency for next time.