All it takes to make all the colors -- except white -- are the three primary colors: red, yellow and blue. You can even make gray, brown and black by combinations and variations of these colors. If you have a tube of white, red, yellow and blue, you can also make pastel variations of the desired pigments. One of the first things an artist learns is how to create a color wheel that consists of 12 colors by just using the three primary colors.
Since you're just starting out, you'll need four tubes of watercolor or acrylic paint, as these are the easiest paints to mix because you dilute them with water. Have a paintbrush handy, a palette, which can be a plate covered with wax paper, a palette knife, pencil and 140-pound watercolor or heavy-duty paper. Draw a circle to fit the page you have, with a 12-inch diameter, if possible. Draw a smaller circle inside it so that you have an outside border that's about 2 inches wide. Divide the border into 12 equal sections so that it resembles the positions on a clock face; place a number near each section if desired. This is the beginning of your color wheel.
Begin the Color Wheel
Add four globs of paint to your palette: red, yellow, blue and white, leaving enough room to mix them as needed. At the 12:00 position on the color wheel, paint that section yellow. Paint the 4:00 position red and the 8:00 position blue. This should leave three empty spaces between each color. On your palette, mix together equal amounts of red and yellow with the palette knife to create orange. Paint the orange at the number two position on your color wheel, leaving a bit of orange on the palette for later mixing. Mix equal amounts of red and blue to make purple, and then paint the number six section purple. Repeat for yellow and blue, adding green to the wheel at the 10:00 position.
The Secondary Colors
The colors you created -- orange, green and purple -- are secondary colors as well as complementary colors to the colors they sit opposite from on the color wheel. If you've created your color wheel correctly, green sits opposite of red; orange sits opposite of blue; and purple sits opposite yellow. The empty spaces left -- six of them -- represent tertiary colors, which are created by mixing primary colors with secondary colors.
Mix Tertiary Colors
To mix tertiary colors, look at your color wheel. In the space between yellow and orange, mix orange with a little bit of yellow to create yellow-orange, which you add to the number one position on the wheel. Continuing clockwise around the wheel, mix orange with red to create red-orange, added to the wheel between them at the number three position. Continue around the wheel this way to mix the rest of the tertiary colors. Yellow and purple make red-purple in position five; blue and purple create blue-purple at position seven. Mix blue and green to make blue-green, adding it to position nine, and finally, add yellow to green to make yellow-green, placing it in position 11 to complete the color wheel.
Black, Brown and Gray
To make brown, mix together blue and yellow to make green. Add portions of red until you achieve the desired brown color. To lighten it, add more yellow. To create gray, start by mixing equal amounts of red and blue to achieve purple. Add to it small bits of yellow until it produces the desired gray. To lighten the gray, add small amounts of white. To make black, mix the brown you created with blue to make it a blue-black. You can also create black by mixing blue and orange or red and green.
Tints, Tones and Shades
If you add white to any color on the wheel, you've essentially created a pastel or tinted version of the original color. To tone colors down, simply add gray to them, and to make them darker, or shade them, add black. Mix your colors with the palette knife first, and then use your paintbrush to apply them to your painting. Once you know the basics of mixing primary colors to make the color wheel, you can essentially make any color that you want. You can also obtain secondary, tertiary and other color options beyond the primary colors, including white, gray and black in tubes premixed for you.