Consistency and repetition in design refer to the reuse of similar design elements like lines, shapes, textures, and colors. Consistency is defined as how often the same design element is used, while repetition is the reoccurrence of those elements. To apply consistency and repetition in artwork, one can paint or draw the same subject multiple times using similar compositions and color palettes, or modify a shape slightly and reuse it. The document provides citations and links to additional resources on consistency, repetition, and their use in visual art.