Consider changing the name of the site to something that doesn't make the site appear to be for moderators only, Should we change our name to make implicit that our scope goes beyond mere moderation?Should we change our name to make implicit that our scope goes beyond mere moderation? touches on this.
Existing members that want to promote the site could think about including the link in various places, if no one knows about the site then no one will come. The various stack exchange profiles that each member has could be a good starting point.