Begin your drawing by sketching your subject lightly on the watercolor paper. Start with the largest objects, and in the process you will determine your composition. If you are drawing on rough paper, apply a bit more pressure since the paper's tooth is very high.
Fill in details after the larger layout of the drawing is done. Begin darkening some of the lines of the sketch as you become more secure about them. Avoid erasing, especially on hot pressed paper, as this ruins the consistency of the paper's finish. Work from the larger elements of the drawing to the smaller. Don't go too dark if you are painting over the drawing unless you want the lines to show through the paint. Watercolor paints are translucent.
Continue directly to the painting if you are executing a watercolor. Proceed with the drawing if that is your final objective by incorporating shading of light and dark areas. Again, develop the darker areas slowly and gradually. Use the side of the pencil for larger areas, and save the softer pencils (which produce richer dark shades) for the end.
Fill in areas with colored pencils or watercolor pencils to add color. Watercolor pencil marks can be washed with a brush dipped in water to produce a watercolor effect.