grow your wiki
Find a culturally appropriate way to acknowledge and recognize dedicated contributors and excellent contributions to your wiki. Empower peer recognition and encourage its use.
Often people get so caught up in the work that needs to be done on a wiki that they fail to acknowledge good work already done. Make your wiki a fertile place by nurturing it with positive energy. Create a culture where people take the time to stop to say "Good work!" to each other every once in awhile. This can be done in fun and creative ways, usually with some kind of graphic icon paired with a brief message.
The CIA hands out shovels for gardening efforts on their Intellipedia wiki, both virtually and physically.