Think before you act. It is hard to do this, as anger is an emotion, and when you feel this emotion you react without hesitation. I have the same issue, but have gotten much better at it. It requires a lot of practice and discipline to manage... when you feel yourself getting angry, remove yourself from the situation, walk, breathe some deep breaths...
It is about being aware of things that make you angry, and also being aware of when you feel yourself losing control, then removing something that triggered it, or removing yourself.