Plan an exhibition around a single theme. The theme could be as simple as "birds" or "the beach" or more complex such as "anxiety" or "hope." Announce the theme in advance to give artists plenty of time to come up with pieces for the exhibition. Using a single united theme makes it more interesting for the viewer and the artists, and makes the exhibit easier to promote as well.
Plan an exhibition featuring artists who use a single type of material. Choose paint, clay, fabric or metal as the medium and invite the best artists in the field to apply. A single-medium show is easy to promote to newsletters, groups and magazines dealing with that particular branch of art. You will also draw in different crowds, as artisans who make raku pottery tend to attract different buyers than those who make traditional quilts.
Plan an exhibition to promote and benefit a local charity. Choose a "Souper Bowl" and have artists create soup bowls to sell, and invite local chefs to make soup for the event. Customers choose their favorite bowl and soup pairing, and take the bowl home at the end of the event. Donate a portion of the proceeds to a food pantry, soup kitchen or other good cause. Select a favorite charity and plan an exhibition that ties in with the organization's needs. Charity events are easy to promote in local and regional newspapers and other media.