Characterization is the way in which authors convey information about their characters. Characterization can be direct, as when an author tells readers what a character is like (e.g. "George was cunning and greedy.") or indirect, as when an author shows what a character is like by portraying his or her actions, speech, or thoughts (eg. "On the crowded subway, George slipped his hand into the man's coat pocket and withdrew the wallet, undetected."). Descriptions of a character's appearance, behavior, interests, way of speaking, and other mannerisms are all part of characterization. For stories written in the first-person point of view, the narrator's voice, or way of telling the story, is essential to his or her characterization.
Characterization never stops! Stay aware of how a character is described, how others react to the character, and how those things change throughout the text. Changes in characters are often crucial to the meaning of a story.