Take a close look at the sculpture you want to display. Identify the viewing angle. Pretend you are the artist to determine where he stood in relation to the piece to visualize the way the artist intended for the world to view his work. If the piece is already on a mount, your task is much easier; you need only identify which angle is front. Although that may initially sound easy -- obvious in the case of busts -- some abstract works require a close examination; some are created with multiple viewing angles.
Temporarily place the sculpture on a hard surface that mimics the viewing angle you just identified. Measure the height from the ground to the base of the sculpture. This is the guideline for pedestal height. Also, measure the size of the base of the sculpture; you don't want it to overhang the pedestal. With this basic information on height and width, begin your search for display pedestals.
Choosing pedestal material is the most difficult aspect of sculpture display. You are ultimately looking for a combination that is pleasing to the eye but that does not overtake the sculpture. "Support" is the key word. The pedestal should support the statement made by the piece. Ironically, coordination is not always the best means of accomplishing this. For example, the juxtaposition of a bronze on a column of chiseled limestone or glass on a wood column make interesting counterpoints to one another. The play of shape, material and substance work together for the best display of the art.
Test it out. Like test-driving a car, ask yourself how it feels. Trust your instincts here. If something is off, you will feel it. Evaluate whether the pedestal has enough substance to support the weight of the piece.