Like many people I was also one of those short tempered people, but then one day somewhere I read what all harm angers does to you as an individual. Slowly I realised that by getting angry doesnt solve anything.I am just causing harm to myself, not only health wise but also a small spurge of anger can cause unrepairable damage to your relations with an individual. It took me some time to acquire this feeling completely, but I think that this realisation really helped me a lot to get curb my "anger instincts".
I do get angry at times now also , but then it goes off very fast and during that time i just tell to myself that this is not good for you !