Anger can be, and often is, the influence of demonic spirit(s). Command anger to go away. Proclaim that you do not want anger. Tell it to go. Here is an example:
"Anger, I don't want you. You are not my friend, and have never been. Leave now, and never return. Go and never come back. Whatever right you had originally, I break it and remove it. You have no right. I plead the blood of Jesus over this anger, and every evil thing associated with it. I want nothing to do with anger, control, violence, rejection, depression, condemnation, or any kind of dark powers or principalities associated with these. By the stripes of Jesus I am a healed. In Christ Jesus, I am an overcome in all things. So, by the redemption power of Jesus, you have no right to be against me, so I command you to leave and never return."
Anger will make a comeback attempt. Be sure to command it away each and every time you perceive it.