It is a really interesting and important question, actually. There are a lot of ways of learning to control your emotions, the most popular are described in the books of Dale Carnegie and others. But if you decided to discuss it on the forum, you need a more radical method. I think you should try an activity that requires control of your emotions, like meditation or... poker. Yes, you can read it here growthselfdevelopment.com, poker affects you positively, you'll learn how to control your emotions quickly if you want to win.