When you can remind yourself that the person who made you angry is a human being with the same kinds of emotions as yours. And, if you are able, to also remind yourself whether you would regret the next day if you were to do what you want to do right now. Another tip is to imagine how you would sound or look if your statements were published in the front page news or shown on a television show for all to see. Yes I wholeheartedly agree that anger can be overpowering at times. But I believe with more logic infused in your inner conversation, you can stop anger at its tracks and prevent major problems as a result.
Keeping promises is hard. It requires us to do things we don't want to do. But keep those promises you must do. Otherwise, do not make them in the first place. But since you have made them, you must keep them, especially if it would benefit all those involved including yourself.