When choosing color for a design, there are many rules you can follow. A basic understanding of color theory and color harmony is helpful, and there are many places online that offer help. Colormatters.com is one that offers some explanation. Some of the key color words to know are hue, saturation, lightness, tint, and temperature/shade. Color combinations can fall into a few color categories: complementary, analogous, triad, and compound. Check out color.adobe.com/create for a great interactive website to see these combinations in action.
If you are unsure how to pair colors, use examples already created. Schemecolor.com has thousands of color combinations and offers free downloads of PNG files. From there, sampling tools within graphic design programs like CorelDRAW, Illustrator, and Photoshop can allow a way to use these colors for a project. Using a keyword search for “art deco posters” demonstrates many great online examples using color harmony in a limited color palette. Often times one to five colors is more than enough for most design projects.