This is a map of the captains colorThe map shows the location of each of the paints. The group on the left are the sedimentary colors. Those in the right are the non sedimentary colors. The palette is just a cut down ice cube tray.
PAINTS
...( sedimentary )
0 - Red
1 - Yellow
2 - Green
3 - Blue
...( non sed. )
4 - Cool Blue
5 - Warm Blue
6 - Warm Red
7 - Cool Red
8 - Warm Yellow
9 - Cool Yellow
PAPER
BRUSHES

Two watercolor paintings showing warm and cool colors. The warm painting on the right is predominately shades of orange and yellow. The cool painting on the left is predominately blue and green. These two paintings serve as demonstrations of how different the feelings are between the color temperatures.
All the following information is applicable to any art medium, not just watercolor painting.
I have more to say about color than about all of the other compositional elements of a painting combined. That is surprising because color is the only one that is totally subjective.
Beyond the basics of color alone (hue), is the concept of darkening the color (shades), and lightening the color (tints).
Shades and tints are referred to as neutrals and semi-neutrals. Semi-neutrals (grays) make the colors sing.
Analogous Colors are colors that are adjacent to each other on the color wheel. Within any group of analogous colors there is very little contrast. Therefore images or portions of images which are analogous are harmonious.
Complementary Colors are those colors exactly across the color wheel from each other. They are of the highest possible contrast. Because of their high contrast, they are useful for calling attention to important areas of the painting, such as the center or interest.
There are three main complement pairs.
Red - Green
Yellow - Purple
Orange - Blue
The last pair, blue and orange are especially interesting. We call blue the color if ice. Orange is the color of fire. We call the analogous colors of blue, cool colors. We call the analogous colors of orange, warm colors.
Nature is painted with cool colors, blues and greens. The cool colors come from the blue sky, also reflected in the shadows and waters, and the green of the vegetation which covers the earth. These colors remind us of the many faces of nature: verdant pastures, adventure, travel, work, play, and also dark woods, lightening, flood, night. In other words all the wonderful and not so wonderful things about the world.
People are painted with warm colors. Red, yellow and orange (brown) hair, pink babies and orange flesh. Warm is the color of love, friendship and mother.
We can use this knowledge to add feelings to our work.
I have a long standing love affair with color. This lesson is will put you on the same path.