ACTION - significant characters cause action and are changed by action. Movement alone does not propel the story forward; while action marks an internal or mental moment of change. In Writing Fiction, Janet Burroway offers the following explanation.

41Character-Attributes

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CHARACTER shown through Appearance, Action, Dialogue, and Thought

Mrs. Withers, the dietician, marched in through the back door, drew up, and scanned the room. She wore her usual Betty Grable hairdo and open-toed pumps, and her shoulders had an aura of shoulder pads even in a sleeveless dress.

APPEARANCE
Similar to interpretation, appearance is more economical and less effective in creating character. It can also show how the character wants the world to be, creating tension.

"I got the tickets," he heard Ethan say. "And they're opening the door in five minutes."
"All right," Macon said, "let's plan our strategy."
"Strategy?"
"Where we're going to sit."
"Why would we need strategy for that?"
"It's you who asked to see the movie, Ethan. I'd think you'd take an interest in where you sit. . . ."
From The Accidental Tourist

Dialogue - shows a character's expression of the internal. It delivers information, provides background, develops scene, advances story, and foreshadows events. Tension appears when speech contradicts thoughts, appearance, action, or authorial interpretation.

When he shuts off the shower, the phone is ringing. A sense that it has been ringing for a long time-can a mechanical noise have a quality of desperation? - propels him naked and dripping into the living room. He picks up the phone and his caller, as he suspected, is Mieko . . . He is already annoyed after the first hello.

Jane Smiley, "Long Distance"

THOUGHT (Parallels Reflection)
A first person author allows the reader access to direct thought, sharing internal decision and discovery. Thought can thwart a character or propel them forward. A tension forms between suppressed and expressed thought. Equally significant is the path a character chooses between desire and action.

Margaret Atwood, The Edible Woman

Action is the most effective way to demonstrate character, although it is not the most economical. It interests, informs, and retains a fresh image. The reader arrives at their own interpretation of the character and a more satisfying experience.