1. Do dua in prayer and after the salah, that calms me down a lot – patience through salah is wonderful and very effective.
2. Read “la hauwla wala quwaata illa billa”. Meaning there is no might except with Allah. And soon enough I calm down.
3. Another thing is to do wudu, that helps also to calm down anger.
4. Drink water.
5. If you are standing sit down, if you are sitting lie down.
6. Staying away from people whom angers you, either on purpose or unintentionally.