The color wheel can 
help

Using a Color Wheel

I put the following together using information from--

Colorwheels

The concepts of color theory/colorwheels can help you when you are trying to choose the right colors to complement your layout. There are lots of cliche color combinations: pink or blue for babies, black and orange for Halloween, etc. These are fine--there's nothing like tradition--but there are times when you're having trouble figuring out what colors to use! Thus, this handout!

A colorwheel is used to visualize color relationships. This can suggest possible color combinations, some of which you might never consider otherwise. Take a look at your pictures before you decide which color scheme to try. The photos will "tell" you which colors to be bring out (not always the most dominant) and the feeling to be portrayed (dramatic, simple, royal, subdued, lively)

A basic colorwheel consists of the primary and secondary colors arranged in spectrum order in a circle: primary colors = red, yellow, blue; secondary colors = orange, green, purple (violet). We all learned in kindergarten that the secondary colors were made by mixing two of the primary colors together; i.e., red = yellow = orange, etc. Click on "Basic Colorwheel" above to see examples.

An expanded colorwheel adds in the tertiary (intermediate) colors to our spectrum--red-orange, blue-green, etc. Thus, we now have twelve colors (generally in spectrum order): red, red-orange, orange, orange-yellow (gold?), yellow, yellow-green, green, blue-green, blue, blue-violet, purple, red-purple. Those are the colors of the wheel we'll work with.

Here are some links on color that I've just run across!
They looked good so I'm adding the links. Give 'em a try!


Now, on to how to combine them!

Complementary colors--colors which are directly across the wheel from each other. They complete each other, thus the term complementary. On the expanded wheel, orange-yellow's complement would be blue-violet; red-orange's would be blue-green.

Analogous colors are separated by one color on the wheel. For example: on the basic 6-colorwheel, purple (violet) and green are analogous--blue is between them. (NOTE: The Pantone Book of Color calls three colors analogous: "A 'classic analogous set' would be 1 primary, 1 secondary and 1 tertiary color that were all immediately adjacent on the wheel." Blue, green and blue-green would be this kind of analogous set.)

Adjacent colors are side by side on the colorwheel. Example: peach (pastel orange) and yellow.

Earth tones/Neutrals--browns, 'dusty' colors, gray, black, etc.
Brown is a combination of all three primary colors (chocolate brown being the vibrant example and tans and sandy brown being the pastel examples) Different shades have more of certain colors than others. Terra cotta is a very orangey brown, mustard brown would have more orange and yellow.

Some more suggestions