Before you speak let your words flow through three gates: Is it true? Is it kind? Is it necessary?
Make this thought the cornerstone of your daily actions. God taught us to "love thy neighbor." How can we do that in a way other than through a loving, honest, and truthful dialogue? If you can't, and it's not important, keep it to yourself.
Little children, let us not love in word or talk but in deed and in truth.