Teach the basics. Show students how to mix colors, do shading and use lights and darks. Demonstrate the techniques and then work with each student individually until he gets them right.
Keep theory to a minimum. In a prison art program, there is no need to spend a lot of time teaching the formal principles of art, such color theory, perspective and composition. Use class time to "create" art.
Encourage your students to express themselves in ways they never thought possible. Prison is a confining place and art can be very therapeutic in helping prisoners work through some of their personal problems and issues.
Outlaw visual clichés. Inmates tend to lean towards stereotypical images of "art," such as a tear running down the face, V-shaped birds and cracked hearts. Tell them they have to come up with other images to convey their emotions.
Promote doodling. This free-thinking art is done while watching television or talking to other inmates, and it can produce good artistic results because control is given over to the pen. Tell students to doodle on newspapers or scrap paper to avoid being accused of wasting supplies.
Insist on productivity that is positive and truthful. Set the standards you expect. Just because the inmates are a captive audience doesn't give them license to be lazy or sloppy.
Display as much inmate art as possible. All artists enjoy having people admire their work. Talk with the warden about the possibility of turning the entrance of the prison into a revolving gallery to display new pieces and encourage artistic inmates. Approach a local gallery about hosting a prison art exhibit.