Certain areas or elements of a room need to be dominant or emphasized.
Variety will keep an area from being monotonous and dull.
– The best analogy for this would be a movie. In a movie there are stars, supporting cast members and general cast members. All parts contribute to make a whole and all important to the telling of the story though some are more important / have bigger roles (emphasis) than the others. It doesn't work if the movie is comprised of all stars; you don't know who to watch or who is more important.
A great way to handle this design concept is to make sure everything in your room isn't a star or "favorite". Good design will be achieved when you realize you don't have to "love" every item or element in your room. Every element has an order of importance, though all are necessary.
You will achieve this through balancing color, placement, and proportion of items and materials you select.
Contrasting color is one way to add emphasis to an element.
– Example: To make a beautiful antique carved fireplace in a deep walnut color the focal point you would want to use a surrounding wall color that would show this off. You wouldn't want to use a color in a similar hue or saturation because the fireplace would blend into the wall and would become its equal.
– For the opposite effect, if you had a really ugly nondescript fireplace you may want to make it the same color as the surrounding walls so it seems to go away.