Been trying to get a loved one to stop smoking? Until they're ready to do it, you may as well save your breath. But when he or she is ready to quit, that's the time to spring into action.

In a paper published in American Family Physician, Michael Bosworth, associate professor in family medicine at Wright State University, and his colleagues outlined a model they call Stages of Change, which illustrates common phases of behavioral change, such as quitting smoking. Here's how you can play a positive role throughout.

Stage 1: Precontemplation
What happens: A smoker won't even consider quitting.
What you can do: Butt out. The smoker has no desire to quit, and badgering "may cause the person to smoke more," Bosworth notes. "They'll take every opportunity to smoke when you're not around."

Stage 2: Contemplation
What happens: A smoker begins to consider quitting.
What you can do: Watch for any cracks in the smoker's defensive armor. As opportunities arise, encourage your loved one to think about how quitting will be beneficial. "The more you believe you have a choice, the more likely you are to decide that smoking is a dumb one," Bosworth says.

Stage 3: Preparation
What happens: A smoker may experiment with smaller changes, such as smoking outside the house or cutting down on the number of daily cigarettes.
What you can do: Stay positive. Praise the smoker for trying. Avoid any negative words if there are setbacks. Judging will not encourage quitting; it will only foster resentment.  Read more.