One is to "tell" them through narration: "Mary was honest and caring." "John was a spiteful gossip."

Another way is to describe the action (still "telling" but a bit closer to "showing"): "John went on and on, with his gossip and rumors. Mary was not pleased."

The third option is to "show" through dialogue: "Did you hear about Betty? She was literally throwing herself at every man at the party. God only knows what happened afterwards!" Mary cut him off, "I don't believe it! I like Betty. I don't like rumors and gossip. I won't let you cast doubt on her character."

Having your characters interact with dialogue truly reveals who they are through their actions and words.

I recently came across an article by trainer and coach, Anett Grant in the Business Journal: 3 reasons why dialogue is the critical catalyst to great storytelling. Although she is talking about storytelling in business and organizational presentations, it fits for most other storytelling too.

Caveat: Be careful about falling into "He said this - She said that!"

The next time you find yourself "narrating" about who your characters are...consider dialogue.
 
Read the article here