Choosing colors is often the most difficult decision when it's time to decorate a room. Generally, professional decorators work with the "three-color" principle: one neutral color and two accent colors (usually one dark and the other light). Some people start with wall color (whether with paint or wallpaper) and build on that (the idea being that walls provide the "backdrop" for the room). Others start with one piece of furniture (something large, like a sofa) and build on that (making it the "centerpiece" of the room's decorating scheme). Also, lighter colors can make a room seem larger and cooler, while darker colors tend to shrink a space and to feel warmer.