• Purchase the correct film for the (slide or print) light under which you will be photographing.  [Slide film: 160 ASDA Tungsten Ektachrome]
• Photograph artwork unframed.  [Note: Exhibitions, galleries, jurors, etc. do not like to look at the framework, only the art piece.  If you send a slide with the artwork framed, it may increase the likelihood of rejection.]
• Use a tripod.  Square up the picture before snapping the shutter.
• Natural but not direct light is best.
• If photographing in daylight, avoid tree shadows, cloud shadows, or patterns of light filtering through houses.
• Eliminate background:  use a simple, clean, neutral background or wall.  It's best to have a black background.  [I use a black cloth for the background.]
• Take several slides of the same piece---at least five.  Sometimes the color on one shows up best at different f-stops.  Duplicate only the best slide.  Keep the originals.  Send only dupes.
• Stop down as much as possible. The higher the number of the f-stop, the more in focus your slide will be.
• The camera should be exactly parallel to the artwork's surface and at the exact center.  If not, you will get a distortion and an angled reproduction.
• Use a 35mm single lens reflex (SLR).
• Use a gray card to check lighting.

Further reading:
Tips for Successfully Photographing Your Work, 400 Sibley Street #200, St. Paul, MN 55101-1928; 1-800-8MN-ARTS or 1-651-215-1600
Photographing Your Artwork, Chicago Artist Coalition, 11 E. Hubbard #7 FL, Chicago, IL 60611; 9page brochure $6.00
Photographing Your Artwork by Russell Hart, F & W Publishing; 1-800-283-0483
The Artist's Handbook for Photographing Their Own Artwork by John White