The human mind has a limited attention and focus span and therefore it is advisable to keep the display simple and uncluttered. Leave a lot of space around. The most common mistake is trying to show too much at the same time. Props should be simple in shape, preferably something that provides a large mass of color or texture, such as blocks, covered boxes or risers.
Always place an odd number of elements in a group. Since it's easier for the brain to zone in on the middle and the arrangement is slightly off balance, the eyes moves around to look at each frame or object. A perfectly balanced arrangement ie even no is dull to the eye.
Use variations of identical elements as that creates a very powerful display mechanism. It's a simple idea but can have a lot of impact on the mind of the consumer and it's hard to miss such a display.
Make sure the items or frames you want to focus clearly contrast with the background. This includes color contrast as well as material texture contrast. For example, don't put a metal frame on top of a glossy background. Try making the background dull and repeated so that the frame that displays important information stands out.
Place one element at the top of the display which is clear and focussed. Below that, in the form of a pyramid, place other elements which provide choice. It's hard to go wrong with a pyramid display.
Paco Underhill, Why We Buy