The principles of visual art are the guidelines for artists to organize the elements of art in an artwork, which makes the artwork aesthetically pleasing and interesting to the mind. While creating an art work, you may use the principles of design, which will improve your artwork many folds -
Control the movement of viewer's eye to the focal point through dynamics, movement tracing, optical illusion, repeating, gradation from warm / dark to cool / light or from large to small size and object sequencing. For example, as depicted in the above artwork, Pink and White stripes on the floor, along with lined up figures on either sides of the artwork, controls the the movement of eye of the viewers from the bottom to the centre of the artwork i.e. bright Blue building, which is also known as vanishing point, located in the horizon line of the artwork.
Balance is the equal distribution of visual weight, which can be achieved by position (symmetrical, asymmetrical or radial), size, texture, value, colour, number of objects and size of an object. In the above artwork, figures (number, size and colour) on either sides are same, which creates a balance between left and right side of the artwork.
Proportion refers to the relative size and scale of the various elements in a design. In the artwork, people at distance are smaller in size and lighter in colour, which give an illusion of depth. Also the Pink and White stripes on the floor, are broader at the bottom and becomes narrow as they move towards the vanishing point.
Rhythm or repetition can be achieved by repeating the elements with variation using progression or transition. As depicted in the artwork, figures on either sides, repeated pink stripes on the floor and skyline pattern, creates a rhythm in the artwork.
Dominance is a focuses the attention to what is most important, which can be created by contrast, placement, focus, size, colour, shape and style such as figurative, abstract and abstract figurative. In the above artwork, main focus is on the female in the middle. As reflected by her casual posture, she appears to be little hesitant and trying to make her way through the unwelcoming people. The bright Blue shade in her right side suggests that she is moving toward the building, which also contains the same bright Blue colour.
Harmony ensures all parts of the visual image relate to and complement each other, which can be achieved through repetition and rhythm of elements. As depicted in the above artwork, pink stripes, figures on either side and skyline creates a harmony in the artwork.
Unity is connection between the elements, by grouping them by proximity, repetition, alignment and continuation. In the above artwork, people on the left are linked with each other using their posture, colour, repetition and so on. Also the background colour scheme involves similar colours such as Magenta Purple, Blue, which integrates various elements of the artwork.
Contrast makes elements different in relation to each other by using colour, texture or value. In the above artwork, black colour figures are in heavy contrast to other colours used in the artwork.
Variety means change in the attribute of an element, to make it different. When the objects are repeated, they become monotonous. Variety of colours, values or shapes may be added to make the artwork interesting. As depicted in the above artwork, the figures at a distance are smaller in size and lighter in colour. Also alternate Pink and White stripes creates variety too.
Rule of Third or Golden Ratio or Golden Spiral or Golden Rectangle (61.77% + 38.22%) and Golden Triangles are standard some design principles, which can be applied to the elements in an artwork.
Break all the above rules, and use your own creativity :-)