Take a deep breath. And another. Then remember, you are the adult.
Close your eyes and imagine you are hearing what your child is about to hear.
Press your lips together and count to ten. Or better yet, to 20.
Exercise to release tension.
Phone a friend.
If someone can watch your child, go outside and take a walk.
Take a hot bath or splash cold water on your face.
Turn on some music, maybe even sing a song.
Drink a glass of cold water.
Rethink about what you want to say and what you want to do.
Empathize and try to understand the point of view of the person who is making you angry.
If you do lash out, apologize.
Encourage your children to practice these techniques also. Empower your children by setting the example for how to deal with anger.