One of the best ways to foster good character is to attach a character trait to a goal your child has. When your child sees the value of the trait by seeing how it helps him obtain his goal, he will never forget the importance of that trait. Teach "please" and "thank you" right away by verbalizing it for young children. Before offering your child a cookie, say, "Please." After you hand it to her, say, "Thank you." Sharing and cooperation are also big lessons in character traits for toddlers. Praise him every step of the way when he shares a toy or a snack with you or a friend. Use discipline techniques should he take things from others. Teach him how to take turns by playing board games with him.
School-age children are capable of learning the more complicated good character traits such as sportsmanship, teamwork, and perseverance. At the dinner table, or during some one-on-one time, ask them, "What does it mean to be an honest/intelligent/caring person?" You may be surprised how much they already know. You can go further by asking, "Is it ever okay to be dishonest?"
Fables, virtue stories, and books are wonderful teaching tools for all kids. Spend some time reading these stories to your child, or have her read to you. Read the same books your teen is reading. Ask her what she thought the lesson was and if she agreed with the outcome. Discuss the traits the characters have.
Your teenager is going through the complicated time of finding his identity. He may test a few of his good character traits in order to do this. Constantly be on the lookout for when he does use his good character traits and praise him for it. Also, look for teachable moments when she tells you what went on in school. Ask your teenager how she would have handled a problem differently.