Maybe try channeling the emotion into a different activity. The typical example is if you feel really frustrated or angry, take it out on a punching bag.
But sometimes, losing your rag and speaking your mind is not only very healthy, but it can also help push a situation in your favour - or at least express exactly how strongly you feel about something.
If you're adamant you need to control these emotions though, then maybe a timeout or some breathing exercises whenever you feel the urge to let your emotions run riot might be a good idea!