Elements of Art
Line: may be straight, curved, continuous, broken; may indicate direction
Light: the amount of light and dark; the source of light
Color: saturation is the intensity of a color, a bright color is highly saturated
Space: perspective, size, figure placement, foreshortening
Shape: may be organic or geometric
Texture: may be actual, like brushstrokes on canvas; or imitative of a surface

Principles of Design
Composition: the overall organization of an image
Balance: In symmetrical balance, either side of the image is equal in weight, and one side may reflect the other. In asymmetrical balance, the sides of the image are unequal.
Contrast: refers to a large difference between two things; for example, green and red, or light and shadow. This term refers to differences between those elements of art in a design. For example, a bright color in a painting will contrast with dull colors. Contrast is used to create tension and interest.
Emphasis: refers to a feature of a work of art that is highlighted or singled out. Elements of art are combined to focus attention on a single element of a composition.
Rhythm: repetition of line, light, shape, etc.

Adapted from Michelle Acuff and Anita Torres, "The Portrayal of the Enemy"