Take cues from the existing elements such as a fireplace, flooring, or countertops. Right away, this will narrow your options down.
By now you probably have an idea of the color scheme you want. Pick a few base color combinations to examine a little closer before buying paint.
Be sure the undertones don't clash. One trick to quickly determine the undertones of a particular color is to look at the other colors on the paint card. You'll see variations of the undertones used!
High contrast, colors opposite each other on the color wheel.
More relaxed, colors next to each other on the color wheel.
One base color used throughout but in varying shades and tints.
Another quick trick to picking an entire color scheme is to use something as a guide, such as artwork, wallpaper or a pretty fabric. Just echo the colors throughout!