Offer to match every dollar your child no longer spends on cigarettes. Don't nag your child to quit. Ultimately, the decision is your child's - focus on helping your child to make a wise one. Help your child develop a quitting plan and offer information and resources. Reinforce your child's decision to quit with praise, an increased allowance, or greater responsibility or freedom.
Kids are quick to observe any contradiction between what their parents say and what they do.
Despite what you might think, most kids say that the adult whom they most want to be like when they grow up is a parent. First, admit to your child that you made a mistake by starting to smoke and that if you had to do it over again, you'd never start. It's not simple by any means, and it may take more than one try and require the extra help of a program or support group. But your children will be encouraged as they see you overcome your addiction to tobacco. Although it may be tempting to get angry if you find your child using tobacco, it's probably the least effective method of dealing with it.