I looked to the inside of a conch shell for my color inspiration. I wanted to add color to my all-neutral bedroom, but still wanted the room to feel natural and somewhat beachy. The color also had to complement the bohemian decor I was using plus coordinate with the original walls since I was only painting an accent wall.
You can never go wrong by looking to nature for a color scheme. Use photos of nature or actual natural objects for help in selecting colors and accessories.
Also, when choosing a true color (not a neutral), go a few shades lighter and/or grayer than the first color you envision. This ensures your room will have a mature, more sophisticated air and not feel overwhelming.