Color harmony is absolutely essential to creating aesthetically pleasing art and design. Color harmony helps avoid any visual clutter or chaos and enhances the visual experience of the objects to its viewer. Understanding color theory including color wheel, primary, secondary and complementary colors is very essential to achieve any color harmony in their art work or design.

The key color is the main color that you choose for your artwork. It could be a primary, secondary, or tertiary color, but it is the one that you want to accent or focus on throughout your piece. Examples include a blue sky, a green forest, or an orangey-red volcano. Once you have identified your key color. 

It is easy to identify harmonious colors using a color wheel and various recommended schemes provided below:

Complementary: Complementary colors are directly opposite each other on the wheel. They are visually arresting, but can be jarring, so it is best to use them sparingly for an accent or pop.

Analogous: Analogous colors are located on either side of the key color along the color wheel. They tend to represent color schemes that are found in nature, and are visually serene. However, overuse of analogous colors can make your painting seem monochromatic, so avoid too much reliance on them unless that is the feel you are aiming for.

Split-Complementary: Split-complementary color schemes use the key color with the colors on either side of its complement, rather than the complementary color itself. This is a safer choice than complementary colors for beginning artists, because it provides much of the same effect without the harshness of a true complementary scheme.

Color Temperatures - The warm colors are on the red, yellow, and orange side of the color wheel. They are fiery, intense, and energetic. The cool colors are on the blue, purple, and green side of the wheel. They are watery, soothing, and calm. When planning your color scheme, consider the mood that you want your painting to evoke, and choose a blend of temperatures that reflect that mood. Black, white, and grey are neutral temperature colors.

Shades, Tints, and Tones - Shades, tints, and tones should also be taken into account when planning your color scheme. Shades are created by adding black to the original hue. Tints are created when white is added, while adding grey creates tones.