Ignore the first link, which is for an ad, and read carefully in the next 5 or 6 links.
At least the first 6 or 7 links here should help.
Design elements and principles, have been used by most people for years these basics elements are color, line, shape, texture, and space. Color represents emotion and allows objects to stand out from the background. Lines represent order and give the eye explicit directions about where to look and how to interpret what it sees. Shape is any type of form used in a display, remembering that the display case or bulletin board itself is a shape. Texture is the visual or tactile appearance of a surface. Space is depth and dimension--objects that are in front of or behind things, around them, or projecting from them.
The Principles of Design are achieved through the use of the Elements of Design. Each principle applies to each element and to the composition as a whole. The Principles are: unity, harmony, balance, rhythm, contrast, dominance, and gradation. Unity … Echoes of all elements relating.
Harmony … Within each element and as a whole.
Balance … With the "weights" of the segments of each element.
Rhythm … Variety and Repetition.
Contrast … Alternation.
Dominance … Within each element. (Center of Interest, Focal Point)
Gradation … Modeling, (3-D effect), Transitions.
Unless what Tim wrote is completely original with him, he needs to cite his source.
Anonymous should NOT quote from any of that unless you know who wrote it originally.