BALANCE
Balance implies that the visual elements within the frame have a sense of weight. Large objects generally weigh more than small objects and dark objects weigh more than light colored objects. The position of the elements is also critical. We unconsciously assume the center of a picture corresponds to a fulcrum. A heavy weight on one side can be balanced by a lighter weight on the other side if the lighter weight is located at a greater distance from the fulcrum.
Another way to achieve balance is through symmetry. Reflections of the landscape in still water are an example of almost perfect symmetry. Reflections can take on an abstract quality that resembles a Rorschach inkblot used in a psychological testing.
Use of NEGATIVE space and POSITIVE space as Ballance
Positive space is where shapes and forms exist; negative space is the empty space around shapes and forms. In the photo below the black area is negative space and it serves to balance the area in which the marmot and rock occupy. Areas of a picture that contain "nothing" are important visual elements that provide balance in an image.
GRADATION
Gradation of size and direction produce linear perspective. Gradation of of colour from warm to cool and tone from dark to light produce aerial perspective. Gradation can add interest and movement to a shape. A gradation from dark to light will cause the eye to move along a shape.
REPETITION
Repetiton with variation is interesting, without variation repetition can become monotonous
CONTRAST
Contrast is the juxtaposition of opposing elements eg. opposite colours on the colour wheel - red / green, blue / orange etc. Contrast in tone or value - light / dark. Contrast in direction - horizontal / vertical.
The major contrast in a painting should be located at the center of interest. Too much contrast scattered throughout a painting can destroy unity and make a work difficult to look at. Unless a feeling of chaos and confusion are what you are seeking, it is a good idea to carefully consider where to place your areas of maximum contrast.
HARMONY
Harmony in painting is the visually satisfying effect of combining similar, related elements. eg.adjacent colours on the colour wheel, similar shapes etc.
DOMINANCE and SUBORDINATION
An artist or photographer attempts to control the sequence in which visual events in the frame are observed and the amount of attention each element receives. Making an element dominant can be done through size and color. Large objects dominate smaller ones and warm colored objects dominate cooler pale colored objects. Another way of achieving dominance is through positioning various elements within the frame. A centrally located object will draw more attention then one at the periphery. However the center is not the best place to position the most dominant element - usually just to one side of the center is more effective.
Another method to achieve dominance is through convergence or radiation or lines. The eye tends to follow these lines to the point where they converge.
COHERENCE
Coherence refers to the belonging together or the various parts of the artwork. In reality these parts may be unrelated, but within the confines of the image their color, shapes, and size form a sense of unity. Visual coherence can be achieved through the use of analogous color and color tonality. It can also be achieve through similarity of shape, color size or texture. However too much similarity can lead to boredom - we need some variety to add "spice" to the image.
UNITY
Relating the design elements to the the idea being expressed in a painting reinforces the principal of unity.eg. a painting with an active aggressive subject would work better with a dominant oblique direction, course, rough texture, angular lines etc. whereas a quiet passive subject would benefit from horizontal lines, soft texture and less tonal contrast.
Unity in a painting also refers to the visual linking of various elements of the work.