If you want more than a monochromatic (single color) color scheme but want a consistent feel, an analogous color scheme is a nice balance between color and calm.

Analogous combinations include: red and orange, orange and yellow, yellow and green, green and blue, and blue and purple. Those are the primary combinations. You can use the intermediary colors such as the popular coastal decor combination of blue and teal.

Analogous schemes are simple and easy. Pick your main color and then pick one or two colors next to it on the color wheel. One combination is to use a transition between two colors. Pick red as your primary color and orange as your secondary and include hues between the two for more variety while maintaining the color harmony.