Place the focal point off-center to avoid a static composition.
The use of prominent diagonal forms tends to make a composition more dynamic.
The repetition of curved forms can create the effect of movement.
Juxtaposition of different types of forms (curvilinear vs. rectilinear, concave vs. convex, etc.) can make a composition more interesting.
When forms are designed to obviously accommodate one another (by going through or around each other or clearly reflecting, echoing or repeating each other’s shape) they will appear much more unified.
Avoid frontality
A skilled designer can even use negative space as a focal point.
Make optimal use of negative space
Repetition: Repetition of elements or forms in a sculpture creates rhythm, unifies the composition and can imply movement.
Texture: Contrast between rough or smooth areas of surface can be used to emphasize other compositional devices.
Focal point: The use of a focal point unifies the composition, and makes the design more interesting.
Scale: By varying the relative size of elements in a sculpture the composition is made more interesting and less expected. Deliberate manipulation of scale (making an object that we expect to be big, small for example) also captures the viewer's attention.
Open/closed form: When an opening is made in a closed form this makes it's interior visible and part of the composition. This adds another dimension to the composition.
Form/negative space: The actual volume of the sculpture is its form. The space around the physical object is the negative space. Negative space, though often overlooked, is as important as form. The form should be consciously designed so that it activates the negative space (i.e. forms interesting voids, hollows or encloses space in an interesting way.)
Balance: Even when a composition is not bilaterally symmetrical its visual weight should be distributed equally enough to achieve visual balance.
Symmetry/asymmetry: Symmetry makes a composition relatively static. Asymmetrical compositions are more dynamic.
Motion: Motion (real or implied) make a composition more interesting.
Linear vs. planar form: A composition made from steel rods, or any other material that visually reads like a line (it tends to look like a line drawing in space) has a linear emphasis. A composition that consists instead of flat or curved solid surface planes is planar. It is often productive to combine planar and linear elements because they contrast markedly with each other.
Rectilinear/curvilinear form: Rectilinear forms are sharp, cubic and faceted. Curvilinear forms are made up of curves. These can be combined quite successfully due to their inherent contrast.
Organic/inorganic form: Organic forms are forms that look as if they were taken from nature (shells, bones, rock formations etc.). Inorganic forms look as if they are machine-made. The contrast between these types of forms can be exploited very productively.
Tension: Tension is an invaluable way to capture the viewer's attention. When the majority of a composition's visual mass is elevated, it creates visual tension. Another way to create tension is to position forms in opposition to each other in a way that implies that they are pushing against each other.
Volume: Volume refers to the amount of three-dimensional space that a sculpture occupies.
Mass: Mass refers to the weight (visual or actual) of the sculpture.
Harmony: A composition is harmonious when it is made up of several elements that have similar characteristics. Harmonious compositions are often visually not as interesting as compositions that display a high level of contrast.
Contrast: A contrasting composition places elements with dissimilar characteristics (in fact opposing characteristics) together in the same composition. The fact that they differ markedly from each other means that they will draw attention to each other.
Color: Color may be used to create or emphasize contrast in a composition, to highlight a focal point, or to create a more harmonious composition.