There are several things we can do, but we should focus on 3 things:
Defining our scope. It's hard to ask good questions when we don't know what we are about. Who are we? What is our audience? Are we catering to fans or participants? If the answer is both how do we do that well?
Generating more content. Once our scope is figured out we need to ask and answer good questions. If we do that the Googles will find us.
VOTE VOTE VOTE. We need high rep users to help keep the site clean and tidy, even after we have moderators appointed. To do that we need everyone to vote more. I'm as guilty as anyone here, we need to vote early and vote often. Make sure you're upvoting good content, but votes and the rep they generate are a really important part of the ecosystem of any site.
By and large is much to early to worry (unless its about getting closed/merged with fitness). Honestly if we can figure out our scope, generate good content, and vote, we should be able to grow naturally.
I should not neglect to mention the typical ways to grow a site (posting good questions on FB/Twitter/Reddit/G+), but I'm honestly not sure how much good that really does if the site's scope and base content is still kind of iffy.