Use your house and its surroundings as your guide.
House: Pick complements to colors that already exist on your home, such as a honey hue on a cedar-shingle roof, red on a brick foundation, or gray on a stone stoop.
Neighborhood: Survey your block. Painting your house a tropical turquoise among a sea of gray and beige will make it stand out—in a bad way. A muted blue or green would be a better fit but still distinguish it.
Landscape: Play off nature. A light green, for instance, might be just the ticket for a property thick with trees and sun-dappled shade, while a dusky ocher would complement the sun-scorched deserts of the southwest.
Weather: The farther south you go, the more intense the sun. So use bright, saturated colors that won't appear washed out in the harsh light. In wintry northern climates, where the landscape is leafless and the sky is gray for much of the year, cooler hues prevail.