Habit forming – ideas for sweet, even temper

Hello, I am at home with my three children 6, 4 and 1.I have just begun homeschooling my six year old and have read Laying Down The Rails (which I absolutely love). One habit I and the children are going to work on in this first year is forming a sweet, even temper. I would love any ideas anybody has had for games we could play, great stories we could read or any other wonderful ideas.

Thanks you very much!