It is likely that just by being aware of elements and principles of design, you will be able to understand and communicate with visual media more creatively.
On the other hand, creativity can be inhibited if one is overly concerned with following rules regarding "proper" design, which can become a cause of "designer's block," just as writers who are obsessed with proper writing style can suffer from writer's block. So it is good to be aware of such guidelines without becoming obsessed by them.
When you are stuck, it often helps to look at examples of similar projects that other people have created for ideas.
Golombisky and Hagen point out that familiarity with the language of graphic design gives you a vocabulary to communicate about visual ideas and culture, and helps you create more effective visual messages. They list the following design elements and principles in their book White Space is Not Your Enemy.
Note: The following are general design principles used by graphic artists. For design specific to photography, see Patterson (2004). For video, the classic book is Mascelli (1965); more current discussions are in Block (2007) and Mercado (2011).
Design elements (basic units) include
Space - the “canvas” or frame in which you are working, e.g., page or screen, as well as the space between items within it.
Lines - can be straight or curved, vary in thickness, designated by a stroke or implied (as when aligned objects or text blocks form an implied line). Lines guide the eye of the viewer, so use of lines is an effective way to lead a viewer to the key part (focal point) of your message.
Size - used to show the relative importance of objects and information
Pattern - repeating lines or shapes, or patterns, can be aesthetically appealing and give a sense of order or wholeness to a design
Texture - gives a sense of depth, which can give visuals a more sensual, tactile feeling.
Value - refers to the tonality of an image. Values are shades of gray from black to white.
Color - creates impact and strongly affects the mood your design conveys. Be judicious in using vivid colors.
Design Principles (rules of good design) include:
Focal point - the center of interest of the design. Be aware of where you want the viewer’s eyes to look.
Contrast - engages the viewer by making the design more visually interesting
Balance - the use of space in the distribution of objects and colors. The sense of balance or symmetry affects the viewer’s emotional response. For example, a perfectly symmetrical design may result in tranquility or boredom while an asymmetrical design may create excitement or anxiety.
Rhythm - the use of lines to direct the viewer's eyes around the page or screen. Vertical, horizontal, and diagonal lines direct the eyes in different directions and convey different emotions.
Perspective - providing a sense of depth (usually thought of in terms of foreground, middle ground and background). Methods for providing perspective include using a horizon line, relative size and scale of objects, linear perspective (converging lines to convey distance), and color and value (darker, richer colors appear to be in the foreground).
Unity - consistency and cohesiveness in the overall design. Everything works together to make one unified whole.