Fluid and effervescent, watercolors attract almost any artist. But as soon as the brush touches the paper, the paint sinks in, making it nearly impossible to correct. Only with good planning can you avoid this trap--and that's hard for eager beginners who rush ahead...and then decide where they're going. With these simple, logical techniques, you can produce a beautiful finished watercolor. The key lies in "tonal layering"--building up successive...