Don't give up.

When someone is trying to quit smoking, relapses are common. They don't mean the smoker has lost the battle. Smoking is one of the most powerful addictions there is; some experts liken giving up tobacco to getting off heroin. Once you accept the power -- both physiological and psychological -- of the nicotine addiction, it's easier to feel like you're on the same side as your smoker: You're both trying to beat this thing, and it's going to take persistence.

"It takes the typical person seven times to quit smoking," says therapist Elizabeth Lombardo. This is totally normal; what's important is to keep the smoker from getting discouraged and giving up. "I tell smokers if they do relapse, it's not a failure; it's data," says Lombardo. "They can learn from what happened."

Analyzing the reasons for any relapses that happen can be especially helpful. "I tell smokers to ask themselves, 'OK, I had a cigarette -- why?'" says Lombardo. "What was happening that led up to that? What can I do differently next time that happens?" Taking this approach is empowering; the smoker feels like he can try again and not repeat the same mistake.

Trap to avoid: All-or-nothing thinking. Just like dieters who dip into the ice cream then give up and eat the whole tub, smokers tend to beat themselves up when they have a cigarette -- then turn around and have five more. This is the result of what experts call "all-or-nothing thinking" -- you feel like you had a cigarette, you blew it, so why bother trying to quit at all?

If you see the smoker in your life falling into this trap, point it out gently: "Just because you had a few cigarettes doesn't mean all those days without one don't count." Keep the focus on quitting, and remind him that setbacks are normal.