Humility is such a hard trait to teach because is example based. They learn from you and how you treat people and how you react to success and praise.
I've always found that failure is wonderful teacher of humility because it grounds you into reality.
Many years ago my younger brother and I used to play in a basketball tournament. My father was a huge basketball fan and was good friends with the other fathers. I remember my dad going to every game proud to see his kids play but he was especially proud of my brothers talent. We were playing the last game for regional championships and we lost by two points. At the end of the game it is customary to shake the hands of the opposing team and congratulate everybody on a great game. Well my brother dropped the F bomb in front of everybody and basically called our team losers because we lost the game for him.
I have never seen my father stand up so fast from the bleachers in disgust and walk over to my brother and explain to him how wrong he was. He made him look at his teammates and realize the personal embarrassment his actions caused.
When we got home my brother was grounded for 3 months. No TV, no sports, no nothing. Basically Food, shelter and school. He served EVERY minute of his punishment. It was kinda sad to watch TV and my brother was in his room looking at the ceiling.
Fast forward a few more months and we had another championship game and we lost again (bad calls). This time my brother shook every body's hand and congratulated everybody on the great game. He was showing a fake smile but he did show humility
I thank my dad for teaching me through that example.