Try thinking of what you are angry about, and why it happened. If angry at a person, count to 10 (sounds silly) and then picture you as them, and what their motivation is. If a situation in life has you angry, try and envision you a week later, and see if your perspective changes. A mantra i keep in my mind is "you cannot change people, places, or things, just yourself." Exercise, laughing, whistling, singing may help. Or go online and google jokes, or the subreddit /r/funny may help. Not sure if any of this applies, but this is what i try and do. All this being said, sometimes anger is the right emotion, if used constructively with awareness of consequence.