Prior to deciding on a color scheme, think about what sort of atmosphere you want to create in the room. With the correct application of color, a number of different effects can be achieved. A bright and breezy, or light and airy, atmosphere can be achieved in the same room as a warm and cozy, or dark and impressive, atmosphere.
Cool colors such as greens, blues and violets visually recede. This means a wall painted in a cool color will appear more distant than it actually is, thus creating the effect of a large, open space. Cool colors are serene and have a calming effect, but remember, the small square of color on a paint chart will look very different when it covers the walls.
Lighter shades of color reflect more light than darker shades, making a room feel larger and more open. This is why white is the most commonly used ceiling color, a white ceiling gives a feeling of height, therefore space. Small rooms and areas with little or no natural light, and darker recessed areas, benefit from the use of light shades. If you have a long, thin room, lighter colors used on the long walls will make the room appear wider.
Warm colors such as oranges and reds advance a room -- the opposite of receding cool colors. Warm colors create a cozy atmosphere because they make the room appear smaller, so they are ideal if you want to make a very large, open space feel more intimate. A long, thin room can be made to appear more square by using warm colors on the small, far walls to bring them closer into the room.
Dark, rich colors such as deep reds, greens and purples make a room feel significantly smaller. For rooms with very high walls, painting the ceiling with a dark color -- or a color that is darker than the walls -- will lower the ceiling, and the darker color can be extended down the top part of the walls to picture-rail height. Darker colors on an accent wall can also be used to create more interest in a square-shaped room. In this case, choose the wall opposite the window wall, because this is the wall that receives the most natural light.