First, begin with a bright white base. You can use either a regular white nail polish, or white gel polish, as long as the surface is white, and preferably matte, so it looks like a real painting canvas. This will allow the sheer colors to come through easier. Pick the colored pencil crayons you'd like to use to make your artists' palette. Use the pencils to color out blobs on the sketch paper. Wet the tip of your brush and smush it into the colored blobs, just the way you'd do with real watercolors. The water will dissolve the pencil crayons and allow the brush to pick up the colors, allowing you paint whatever designs you want on your nails. The thinnest brushes will offer you the most control.