The watercolor pencils that I use come from Faber Castell, and they come in many different shades. There are many different watercolor pencil techniques, but my favorite method is sketching out my painting with a regular pencil, coloring it in with the different colored watercolor pencils, and then applying water with a brush. You can also dip the tip of your pencil in water, and then draw onto dry paper, but this method uses up the pencil lead very easily. Another way to use your watercolor pencils is to slightly wet your paper and draw with a dry pencil. This creates unique bleeding effect.
What I love about using these versatile pencils is that you will have the watercolor paint look, but all you really did was draw. The reason I usually sketch is because painting can be difficult, as you have to have a bunch of different colors to get the right values. When the paint dries you can't blend the colors, but when it's wet you can't add more paint. Watercolor pencils are similar to this. It is easier to do all of your shading if you add all of the color before applying a little water. From my experience you can't really put new layers with watercolor pencil, as the color is thin and will be a little see through.
Try using different mediums in addition to your watercolor paint, such as pens or a different type of paint such as acrylic, which is my other main painting medium. Just have fun using your watercolor pencils, and make your own masterpiece!
This is watercolor pencil painting of a rosebud.