The way in which you shade letters depends on their shape, how round or flat the letters are, and how you wish to show that they are three-dimensional. To draw and shade 3D letters, you need scratch or practice paper, a drawing implement, and any colors you want to include.
Choose the size and shape of your letters
Write the letters or message you want to use. Make sure they fit on the page at the size you want them. Draw sample letters on scratch paper to determine how round or sharp you want the corners and how thick or thin you want the lines. Draw your letters in pencil first before coloring with a more permanent medium.
Plan and outline the shadows
Determine the 3D shape of the letters and how they are to cast shadows. Shadows for 3D letters typically fall behind the letters or on one side of them. Choose the direction of light. Outline the shadows starting from the letter and going directly away from the light source.
Shade as needed
Shadows cast on curved surfaces grow darker as they get closer to the edge. Fill in the shadows starting from the darkest edge. On the other hand, shadows cast on flat surfaces have the same shade throughout. Fill in these shadows beside or behind the letters. Use the flat side of the pencil lead or a scrubbing tool to keep the shadows an even shade.