If you're looking for a clean, sophisticated look, the monochromatic color scheme is for you. A monochromatic scheme is the easiest to create with subtle variations in lightness and saturation of a single color. The result is a look that's calming, organized and buttoned-down.
You might think that opposites attract, but it's the colors adjacent to each other that really offer the nuances. Pick one color as a dominant color and use the colors that are adjacent to it for accents, to give the scheme some texture and visual interest.
If you've picked a dominant color and you're looking to create contrast, pick a color directly across the wheel for a complementary scheme. The two colors will intensify each other for a lively, vibrant scheme.