If you have ever asked yourself how much room should there be between pictures here is an easy way to check..the hand test. I use this every time when hanging pictures also use your eye as to the placement on the wall. Pictures typically are placed at eye level (avarage heighth 5'6")or "58 inches from the floor.

This wall hanging is very pleasing to the eye working horizontally, as on a sofa wall or a hall entrance, prints grouped in odd numbers are visually balanced, giving volume without crowding.

There are terms we decorators use everyday that of Symmertrical which is the mirror image.

If you have a selection of pictures that are similar in subject matter, size and framing, consider a symmetrical grouping to create balance. Symmetrical collections are often used to create the popular gallery effects, above large pieces of furniture, such as sofas and above mantles

This grouping is Asymmetrical this effect is a bit harder to achieve it takes some patience, the right art work, and a good eye. I like working assymetricaly when I have multiple prints of various colors and sizes and have a large wall to work with. This grouping works best if you have a selection of dissimilar pictures with at least one common element, such as subject matter, use an asymmetrical grouping for a more organic balance.

If you would like to read more on this subject check out one of my favorite sites Decorating Digest for many other ideas on hanging pictures and decorative wall techniques.