I cannot express how important it is to learn the colors in your palette. Find out how many new and different colors you can create by combining the colors in different ways.
Glazing watercolors is a great way to increase the amount of colors you can create and to create colors that glow through other colors. Glazing watercolors is putting a wash of transparent watercolor over top of a color that is already dry. Through glazing you can create colors that glow, you can create color you cannot create by mixing two colors on your palette and applying the mix to your paper.
Practice glazing by painting a variety of one color squares on a piece of watercolor paper. Allow the squares of color to dry completely. Then using transparent colors, place a swash over top of the dry color. Bring the transparent swash of color beyond the dry square. Repeat this with a variety of colors. By bringing the swash beyond the dry square, you will be able to see the swash of green applied over the yellow square creates a very pretty glowing yellow-green. The light red creates a pretty orange that has a gorgeous glow of yellow. You can intensify one yellow with another yellow.
The glazing technique can be used in a variety of watercolors, from flowers to barns and more. The key is to glaze a transparent color over the top of any dry color.