When I was a child, I was a very angry person. I broke windows and got in fights, including a stand-off against a teacher, threatening her with a chair over my head. Doctors gave my parents the option of using drugs to control my moods, as is common place today. My parents did not opt for that easy option, instead choosing to guide my behaviour though training which would provide me the tools to get a hold of my own anger.
Anger management needs to come in two different relating parts. These are short term strategies for when you feel the anger coming on, and long term strategies for preventing the buildup of anger. I will discuss short term options as these are most often what is needed immediately to prevent harm to friends, family, property and importantly yourself.
Often we feel powerless to control our anger, even though we can sense it building up, and may even know the cause. The first action you can take when you feel yourself becoming angry or getting annoyed is to remove yourself from the situation. A good excuse to be able to leave most situations which will be accepted without being rude is excusing yourself to go to the toilet/bathroom. Once in there give yourself all the time you need to gain control, if you can't do this naturally by yourself, that's okay and quite normal, just move on to one of the next strategies. If you find you can't remove yourself from the situation you can also try these next strategies.
Close your eyes and count. Instead of counting fast as your anger encourages you to do, count slowly visualizing each number in your mind. You may find that visualizing the numbers in colours like green or blue may add to the calming effect. Another thing you can do in your mind instead of counting is sing the lyrics of a song that makes you happy, again focusing on the lyrics. If you are in a situation where you have a drink (preferably non-alcoholic) or food, you can take a drink or pop a piece of food in your mouth but before swallowing taste the food/drink. See if in your own mind you can taste what it's made of, see if you can select out certain flavors. These may sound silly but that's okay, they all share a similar element distraction. By focusing your mind on something irrelevant to the stimulus that is annoying you, you give your mind the ability to move away from anger back into a neutral state.
Another thing you can try depending on the appropriateness is hugging. This may be either hugging the person upsetting you, hugging a friend/spouse/partner, a pet or an inanimate object such as a toy or a pillow. A hug will break you away from the immediate situation, as well as letting your brain produce some positive feel-good hormones.
One strategy I used often as a teenager, although I don't recommend it as a first option is rapid emotional conversion. This requires removing yourself from the situation and other people. As most people would agree anger is a pretty stupid thing, so why not do some stupid things (in your mind) with your anger? Use your current anger and play with it in your mind, think evil things if you wish preferably applying that anger in your mind away from the stimulus that caused it. Play with the anger and see what sort of stupid angry things you think. When you have thought of some really stupid things laugh. Anger is stupid, and in the right light can be funny, if you can convert anger to laughter then your halfway home.
Controlling our anger long term is a lot tougher and requires a lot of personal effort. If you have accepted that you have anger and that it is a problem for you, you have made the most important step. To gain control of your life and to stop anger being a part of it, I do not suggest spending too much time with online strategies but instead seek one on one help with a trained professional, who will be able to guide you and give you help with things late relate directly to you and will help you personally. Congratulations on wanting to be a better you, or if you read this for a friend congratulations on wanting to be a helpful friend.