Coat the walls with bright shades of blue, green or yellow paint. Neutral black and white walls don't do any favors in poorly lit small rooms. Reds should be avoided unless you want to make a bold statement. Bright reds are considered an "aggressive" color. Rather than adding bright warmth, a red color dominates the space, and it should only be used if all your furniture pieces and wall art are relatively neutral-colored.
Paint using a semigloss or high-gloss sheen. If you're using existing paint that doesn't contain a glossy sheen, you can increase the sheen by adding a polyurethane topcoat to the small room's walls. Glossy finishes reflect more light for a brighter space.
Paint an accent wall based on natural light sources. Choose a wall that gets a lot of sunlight, and paint that wall a different color from the others. This draws attention to the accent wall, especially during the daytime, making the entire room feel flush with sunlight.
Apply white paint to the trim. Darkly painted or natural wood trim takes focus away from your brighter wall color. White and neutral off-whites frame the wall without dominating the space.