First few months sets the tone. Watch it carefully then.
Invite people to visit and contribute. Invite 20 at a time. Expect only 5 or 10 to do so and only 1 or 2 to write. Invite 20 more a few days later.
The best contributors are people with some name recognition. Really famous people already have too much invested in their name to risk signing it on a wiki (in their opinion anyway).
Write a page every few days yourself.
Add paragraphs to many pages. Do web searches and add pointers to related sites with brief reviews or quotations from the sites.
Try to keep your signature from being the only one.
Ward on public space: http://c2.com/doc/space.html
Also see Participating In Wiki