Here are some thoughts on anger:
---Get clear about who or what you are angry at:
A person? What exactly did they do? -- describe as objectively as possible as if a video camera had recorded it.
A situation or event that occurred? -- this could involve multiple people, yourself, plus unforseen circumstances, describe as objectively as possible as if a video camera had recorded it.
An idealogy or group of people? -- perhaps something political or religious that feels morally wrong and beyond control -- get clear about what you believe and value, as well as what is and isn't in your control.
Yourself? -- this could be a particular standard of competence that you thought you "should" be able to maintain -- Shift to seeing that we are all human and make mistakes, and then see the situation as a learning experience by taking note of what you would do differently next time.
---Get clear about your feelings of anger what (level of intensity and where in your body you feel it) and if you are also feeling frustrated or disappointed.
Anger is motivating but if you are too angry (out of control) or not clear about what the problem is then it isn't very useful.
---Understand the root causes of anger:
1) you think that something should or ought to be different than it is -- because it is unfair, immoral, or "wrong"/"incorrect" -- and you are judging a situation according to your internal principals (which may be different than the other party involved).
2) the situation seems very unpleasant or unbearable.
3) there is a problem that seems difficult to change and you feel a lack of power to implement changes or it feels like it is out of your realm of control.
---Shift the anger into solving a problem:
Get clear about what the problem is and what you would want instead. Get specific about what you would want, but also come up with several options for solving the problem.
Get clear about what the other side feels and wants -- sometimes they want the same end result but just have a different strategy for getting there. Find a solution that both sides can feel good about (there are a lot of modern resources on conflict mediation).
If you were harmed, decide if you want to ask for acknowledgement or restorative justice. (Remember that vengeful punishment will most likely result in perpetuating a cycle of violence, which will bring more harm than good. And trying to "teach" someone will only result in that person digging in their heals furth to defend their position).