R.T. Kendall has this good advice on what should be coming out of our mouths when talking to, or about someone else. It is an excerpt from his excellent article on "Stop Playing God," which you can read here.
One acrostic I have found helpful is built on the word "NEED.: When speaking to or about another person, ask yourself if what you are about to say will meet the person's need.
Necessary—Is it necessary to say this?
Encourage—Will this encourage the person? Will it make him or her feel better?
Edify—Will it edify? Will what you say build the person up and make him or her stronger?
Dignify—Will it dignify that person? Jesus treated other people with a sense of dignity.