Line:
Lines help draw the eye in a specific direction or to a specific object.
Shape:
Symbols that are used to convey emotion and meaning that are understandable across cultures. For instance, a triangle seems dangerous because of the connections to sharp edges, spears, arrowheads, etc.
Mass:
Affects how something appears to weigh. Can be affected by color, tone, density, etc...
Tone:
Shading, it involves how light is affecting an object.
Color:
Affects the emotional feel of the object due to natural and cultural associations with each color.
Texture:
To show depth, and to show how something looks like it feels.
Balance:
Visual Weight, depicting the objects equality throughout the piece, if it is even.
Proportion:
The size and mass of one element of the object in relation to another.
Rhythm:
The speed at which your eye travels around the object.
Emphasis:
What point in the design your eye lands on first.
Unity:
Connectivity, it depicts the connection of the whole piece.