Apply the Letters stencil and pick a letter to add to your painting surface. Make sure that the stencil lies firmly on the background so that your result will have a nice sharp and consistent edge. Then spray over the letter with a color of your liking.
If you don't want to create only outside shading on the letters you may also fill the insides. For this, first spray the shadows of the desired letters. Then apply the masking tape over it and cut out the inside area with a scalpel. Here you may implement other colors and structures, just as you like.
Combine the Letters stencil with a motif. First, spray your motif, and once it is finished, add your letters. This way, you can create individual illustrations, e.g. for postcards, or quick and easy lettering for a T-shirt.