One of the easiest ways to change the feeling of a room is with color. I happen to like pops of red, so I often like to paint one wall in a common room in a rich ruby. The area over my fireplace was perfect for that. Warm colors—red, especially—enliven a room, making them good for the areas where you plan to entertain. But sometimes a whole red room is too overwhelming, so confining the color to one wall tones it down while still introducing the desired effect.