To give depth to your artwork, your subjects need to have a three-dimensional aspect. Your drawing surface is flat, and to create a three-dimensional appearance, you create an illusion. This illusion of depth is given by shading and perspective. Shading is the presentation of shadows and highlights in a way that creates a three-dimensional effect. Perspective is simply that things further away from the eye appear smaller, and part of an object will appear smaller relative to their true proportions.
A third-less obvious element to creating the illusion of three-dimensions is the focal point. For example, if you take a camera and focus on a subject that is close to you, the background will be out of focus. This same illusion can be created in your artwork by creating blurry backgrounds.
Here, I am sharing some tips and tools that I use to create shadows and highlights when using graphite as a medium. In my journey of continual learning, one of the key things I was taught (by my father) was the use of graphite powder for shading. Graphite, which is simply a crystalline form of carbon, can be purchased in powder form. Alternatively, you can create you own by sharpening the end of your pencils on sandpaper and using the graphite dust off the sandpaper.
For graphite powder use, I use a Filbert 10mm brush head for large areas, a 6 mm flathead brush for medium areas, and a 3mm dagger shaped brush for detail shading. It really does not matter what size, shape brush you use, if you have control of your brush strokes. I prefer the Filbert head as you can modify the surface area that you have in contact with the paper, just by varying angles of brush stroke.
Before applying ground graphite, I collect a small amount of graphite on the brush, shake off excess back into my jar of powder, and apply brush strokes on a scrap piece of paper, until the shading on the scrap is about the right consistency (shade) that I want to apply to my work. Obviously, the shade will get lighter until you collect more powder on your brush. For light shades, such as pale skin tones that are lit up, I use the slightest bit of powder on a brush. With these techniques, you can create exceptionally smooth textures (like skin), using this form of shading for your final artwork, laying a foundation for further pencil shading, or for creating shadows to enhance a three-D effect.