I don't have children, but I was a kid once! I was fortunate to have parents who taught me to be thankful. It wasn't something they sat down and talked to me about, it was more about setting an example. I also had wonderful aunts who set a great example in being kind and generous and giving.  These are things I've carried with me and I think it's important for parents to teach their children well.

Teach Manners: Please and thank you go a long way!

Set the Example:  Volunteer, show gratitude, treat others with kindness

Make it Fun: Take turns saying what you are thankful for, volunteer as a family, read books together that teach generosity.

Positive Reinforcement: When your kids do something nice for someone else--let them know you are proud of them!