Sale of cigarettes or smokeless tobacco is illegal to anyone under 18. Let retailers know that these rules are important to you. Praise retailers who comply with the rules. If they have already tried tobacco, talk about addictions. It is easier to quit before they get hooked.
Nicotine tricks the body into believing it needs the drug to survive.
The easiest way to quit is to never start. Most teen smokers report that they would like to quit, but can't. They also report that if they could choose again they would not smoke. If they are regular smokers, encourage them to quit. Support their efforts.