Charcoal is a medium artists use for drawings and for setting tonal values. The chalklike behaviour of charcoal makes it easy to correct errors and allows an artist to draw without worrying about details. This convenience makes it easy to purposely blend and to accidentally smudge. An artist will use his fingers or a tortillon to blend and modify strokes, and will use techniques to prevent smudging such as modifying the direction of working on a drawing or by using a fixative.
Work the charcoal drawing from left to right if you are right-handed, and from right to left if you are left-handed. This will prevent your hand from resting on the charcoal.
Draw from the top to the bottom of the paper. If you are not able to do this, tape a piece of paper over the charcoal area to prevent smudging.
Use a transparent fixative. You can find fixatives in a jar or a spray can. Choose between a workable or permanent fixative. The workable fixative helps prevent smudging while working and a permanent fixative seals and protects the charcoal once the drawing is completed.
Use may hairspray instead of a fixative. When spraying a fixative, hold the can 12 inches away from the drawing. Spray across and not straight down. Always spray outside or in a well-ventilated area.