Frame your words. Connect your words with your mind rather than let your mouth run away and then try to catch up with your mouth. Unnecessary talk dulls your mind. Efficient use of words puts you in control of your mind. Medium people speak about places and things.
Big people speak about ideas.
The words you choose determine the type of person you'll be. Don't talk without a purpose. If you can't identify the point, there probably is none. When people find themselves talking too much, they refrain from all conversation except for Torah study. Try experimenting for one hour without talking.