Even if the person knows that you do not like her behavior, your own distaste for the behavior might not be enough to make her want to change it. To attempt to change her mind about changing the behavior, try giving her information about the habit that makes it seem undesirable or worth changing.  For example, you could try saying, “Joanie, I don’t know if you know this, but smoking can be really harmful and lead to lung cancer. My uncle was a lifelong smoker went through chemotherapy for lung cancer last year, and it was really hard for my family to see him through that painful time in his life.” If you have been suffering in silence, or trying to drop subtle hints, these few steps may solve the problem entirely. Often, information alone is not enough to change a behavior; however, information combined with your opinion as a trusted acquaintance, friend, or family member might be enough to convince a person to attempt to change. Once you've made your wishes clear, back off and do not belabor the point. Nagging the person if she already knows what's wrong is unlikely to have a positive outcome. The person might not even realize that he is doing this behavior and therefore might be open to changing it. For example, it might drive you crazy when your friend chews with his mouth open, but if he's done this his entire life, he might not notice that he’s doing it. Remind the person gently what he is doing and how he could stop. Be polite.  For example, you could say, “Ed, Could you please chew with your mouth closed? The chewing noise bothers me.” Be nice, especially if the person is unaware. You should not say, “Ed, you’re chewing like a cow. Cut it out!” This strategy will only work if the person is doing the behavior essentially by accident. If you want your mom to stop smoking and you make her aware that she’s smoking every time that she smokes, your strategy will probably be ineffective. Positive feedback is better at the beginning of a person’s process of change because it encourages the person to feel more committed to her goal. It also improves your relationship with that person. For example, if you are trying to get your friend to come to the gym with you more frequently, you should, in the beginning of the process, say something along the lines of, “I know you would be great at this spin class, because you were great at kickboxing last week. I would have more fun if you came with me. Let’s go on Tuesday!” If the person you’re trying to change does the behavior you want him to do (or stops the behavior you dislike), reward him! If your husband doesn’t smoke for a week, take him to do something he loves, like bowling or golf. Be an encouraging force, rather than a negative force, in the person’s life when he does something right. Praise good behavior using lavish, enthusiastic praise in whatever form the person understands best. Physical affection if appropriate, kind words, gifts, doing things for the person, etc. Connect the good behavior to you being thrilled with him and his life being better as a result. Changing behavior is not about conquering temptations. If your friend is trying to lose weight, do not take her out for ice cream on Friday night. If you’re trying to get your wife to be on time, be sure to give her an ample amount of time to get from her work to date night. For example, if your best friend is a recovering alcoholic, do not have her birthday party at a bar or a dance club, where there is likely to be a huge amount of temptation to drink. Instead, bring her somewhere where there is less temptation, such as pottery painting or bowling. The effectiveness of this technique depends on the behavior you want to change. For something like quitting smoking, losing weight, or dealing with addiction, these groups can help the person stay motivated and engaged socially in achieving his goals.  Even for smaller behavioral changes, such as helping your brother spend less money, recruit his close friends and your family members to help with the goal in little ways. If they are aware of the goal of the behavior change, they will support him. If the person whose behavior you want to change has a drug or alcohol problem, he also might find it helpful to go to a support group, such as Alcoholics Anonymous, where other people in the group are going through the same thing.

Summary:
Give the person information about the behavior that will encourage her to change it. Increase the person’s awareness of the negative behavior. Give positive feedback. Reward good behavior. Make good behaviors easier than bad behaviors. Offer a support network to the person.