“Harmony can be defined as a pleasing arrangement of parts, whether it be music, poetry, color, or even an ice cream sundae. In visual experiences, harmony is something that is pleasing to the eye. It engages the viewer and it creates an inner sense of order, a balance in the visual experience. When something is not harmonious, it’s either boring or chaotic. At one extreme is a visual experience that is so bland that the viewer is not engaged. The human brain will reject under-stimulating information. At the other extreme is a visual experience that is so overdone, so chaotic that the viewer can’t stand to look at it. The human brain rejects what it can not organize, what it can not understand. The visual task requires that we present a logical structure. Color harmony delivers visual interest and a sense of order. In summary, extreme unity leads to under-stimulation, extreme complexity leads to over-stimulation. Harmony is a dynamic equilibrium.” (http://www.colormatters.com/colortheory.html)

To achieve harmony we can choose many different colors, similar colors, complementary colors or colors with contrast:

“Analogous colors are any three colors which are side by side on a 12 part color wheel, such as yellow-green, yellow, and yellow-orange. Usually one of the three colors predominates. Complementary colors are any two colors which are directly opposite each other, such as red and green and red-purple and yellow-green. In the illustration above, there are several variations of yellow-green in the leaves and several variations of red-purple in the orchid. These opposing colors create maximum contrast and maximum stability. Nature provides a perfect departure point for color harmony. In the illustration above, red yellow and green create a harmonious design, regardless of whether this combination fits into a technical formula for color harmony.” (http://www.colormatters.com/colortheory.html)

Now, even the same color can have different readings when placed near different colors:

“Observing the effects colors have on each other is the starting point for understanding the relativity of color. The relationship of values, saturations and the warmth or coolness of respective hues can cause noticeable differences in our perception of color.” (http://www.colormatters.com/colortheory.html)

Computer-specific bells and whistles, such as interactivity and animation, will let you blend online photography with the elements of cinema and other visual arts. However, these are only extras. A carefully selected and integrated still photo per se can have a surprising impact in a design composition. It can be an excellent eye-catcher and a drastic improvement even for a beginner’s work.”

(from http://www.webreference.com/dlab/9708/)

The two main categories of typefaces are display type and text type. Although they are frequently interchangeable, their improper use can seriously damage the success of the publication. Typeface selection is very personal, and although subjective, long established rules of proper use should be observed. The most important rule dictates that the designer evaluate and analyze the project, the available visual elements (photos, logos, graphics, texts, etc.,) and then select fonts that portray a visual message in alignment with the message — the typography should look like the product, subject or message. This is of paramount importance.

So to achieve this goal, the designer must ask questions about the nature of the subject. Is the message calm and dignified? That might call for a classic, old style serif font. Is the message fun and playful? That might call for a mixture of sans, and a modern humanistic display. Is the message serious or forboding? Then perhaps angular, sharp corners and heavy blacks are in order. It is up to the designer to correctly identify the personality of the project, then search for the typeface for both body text and headlines that best personifies that personality and emotion.”

(from http://www.graphic-design.com/stock_layouts/typography.html)