Nothing softens and enriches a wall like a rich, warm faux wall treatment. There are hundreds of possible combinations and techniques.
Most faux treatments copy nature in one form or another. Natures examples may be found in the rich patinas found on rocks in desert areas, patterns seen in Carrera Marble, limestone aging processes that may be found on old French, Tuscan or Mexican walls.
A good wall treatment should generally look and feel organic and natural. There are exceptions in more contemporary looks including metallic foils and holographic applications.