Pay it forward...
Just throwing this out there (I don't know if it's really a good idea).
On meta.SE, every month we select a different small site (the "target" site) to help out. During that month, we become active at the target site: we make noise and get the site noticed. We cast lots of votes, ask lots of questions, make lots of edits. Whatever is needed, and whatever we can reasonably do.
The next month, which site do we help out? From the sites that have yet to receive help, we select the one that has been the most active in helping out.
I feel many veteran Stack Exchangers could ask a reasonable question at a site like Earth Sciences, something that's taught in school. (E.g., just read a random Wikipedia page and ask about whatever claim has "" next to it.) It may not be so easy at more specific sites.