A complementary color scheme (indicated by the blue line on the chart) consists of hues that are opposite on the hue wheel. For e.g: yellow and violet, blue and orange, blue-green and red-orange… you can make six pairs this way. They are farthest apart on the wheel and create dynamic contrast. Their temperatures will be opposite. When viewed next to each other, they enhance each other and create a vibratory effect. This scheme needs to be used with some care, else it can look a bit jarring. Try making one hue more dominant than the other to create harmony. The two hues used in tints, tones and shades as well as a combination of themselves and with neutrals can make an array of colors and need not be limiting.
A split- complementary color scheme consists of a hue and hues on either side of the complement, excluding the complement itself. For e.g: red, blue-green and yellow-green or blue, red-orange and yellow-orange or blue-violet, orange and yellow.
An analogous-complementary scheme (indicated by the orange line on the chart) consists of three analogous hues and the hue opposite it. For e.g: Red with blue-green,green and yellow-green. Use the complement as an accent color rather than let both sides of the wheel vie for attention.
The split and analogous complementary schemes are often times more pleasing than a pure complementary scheme.
In nature, you can see these sets in the pale-yellow deep-violet of some iris or sunset skies; blue orange in bird-of-paradise or autumn maple leaves against a blue sky; pale red-violet pale yellow-green of young ornamental cabbage… Red-green is very common in nature, I`ve used it here in this painting of Geraniums. Raw sienna is the almost neutral accent color, though its not seen in the photo.
Here, I`ve made an abstract using blue-violet,violet,red-violet and yellow:
Watercolor Journal 