In general, artwork should be hung so that the center point of the picture or grouping is at about eye level for the average person. While this won’t be possible in every situation, it’s a good guideline to keep in mind.
Another technique to remember is that a grouping of pictures should be thought of as one unit. Test an arrangement of pictures by laying everything out on a large table (or on the floor), playing with combinations until you hit upon one that works. Laying them out on paper is even better since you’ll be able to trace around each object and determine where picture hangers should be installed. Tape the paper up on the wall as a template for picture hangers and you’ll be done in no time.
You can also lay out pieces of scrap molding (or tape) onto the floor to form the “outside” bundaries of a picture grouping — the measurements within which the smaller pieces of art will be set. This is useful when a particular wall has certain boundaries that must be observed (such as a chair rail, windows, heating vents, and the like) and helps keep your arrangement the proper size.
Choose smaller pictures for narrow walls and larger works for big wall spaces.
In general, when hanging art over a piece of furniture it should not be longer than the width of the furniture.
Choose artwork that underscores the mood or theme of your room’s decor.
Is the room vibrant, pastel, or neutral? Is your furniture casual, formal, modern, or traditional? These are clues that will help zero in on the type of artwork that compliments the color and scale of a room. Vibrant colors bring excitement to a room while neutral colors are more calming. Which do you prefer?
Keep in mind that one large painting makes a statement and keeps things simple. It can also call attention to the focal point of the room which is often the fireplace.
Landscape art is one good way to visually open up a smaller space. The view of a distant horizon acts as a sort of “window” giving the impression of a faraway vista. You can add the look of a “window” to a small or windowless area by hanging landscape art.
The use of line is sometimes overlooked by home decorators, yet proper use of line can set the mood in a room. Horizontal lines tend to elongate, widen, and emphasize a casual decorating scheme. Vertical lines however, tend to be more formal, add to the illusion of height, and can seem more elegant and refined.
You can find these and many more interesting tips on decorating your home with art by following the link to about.com-interior decorating.