* Brighten Room The common solution to a dark room is throwing white paint on the walls, to reflect more light. But the lack of light generally makes the white room look washed-out and gray. A better solution is to use a warmer and deeper color, which often can provide the luminosity missing from the room. Yellows are particularly effective, because the color value can be kept light enough while still adding warmth.
* Enlarge Living Spaces If you have light-colored floors, choose a deeper wall color and a light ceiling color to reflect the floor. Walls will appear to recede above the floor. If you have dark floors, keep walls and ceiling light and the same color. Eyes are attracted to contrast - high contrast between walls and ceiling closes spaces.
Some people think they can lift a ceiling by painting it white. That is often the case, because a white ceiling reflects more light. But if there's already plenty of light, similarly colored walls and ceiling can make a room appear more open and atmospheric.
* Achieve A Sense Of Consistency Use the same trim color throughout a number of rooms. The wall color in each room will make the trim appear different. Keep the trim lighter than the walls. Using darker trim colors can be beautiful but it is much more difficult to pull off.