Paint can make small rooms seem larger and more spacious. Depth can be created through a number of tricks, including color selection, contrasting colors, focal points and color mixture. Once the walls are painted, accessorizing and furniture arrangement are additional tools you can use to make your room seem larger than its actual size.
Use contrasting colors between the room you want to add depth to and the adjoining hallway or foyer. If you paint the hallway or foyer in dark colors, and then paint the room you're adding depth to in a lighter color, it will create the illusion of darkness giving way to light, or light receding into darkness (depending on your vantage point). The contrast will make the lighter room seem larger and deeper in comparison to the smaller, darker space beyond.
Paint the ceiling and walls according to the accents in the room. If you have a light-colored rug, paint the ceiling a slightly lighter color than the walls. This will make the floor and ceiling seem light, creating the illusion they are moving away from you and the walls, and causing a feeling of both expansion and depth. If you have a dark-colored rug, paint the walls and ceiling one unified light color. This will create the illusion that the room is moving both up and back from the floor.
Choose a focal point in the room, such as the fireplace, bookcase, entertainment center, bed or table. Paint the wall with the focal point a darker color than the other three walls in the room. This will make it seem as if the rest of the room is drawing away from the darker wall, thus adding to the illusion of depth and space.
Paint a trim to contrast the primary colors of your walls. Whatever color you paint your walls, make your trim lighter. This will make it seem as if the walls are receding.
Paint the walls a mixture of two shades of the same color. Mixing shades together adds depth to the color and to the appearance of the room. Make sure the color you choose is light; "cool" colors such as blue, green and blue violet recede, while warm colors such as red, yellow and orange advance.