Promoting your forum? Any tips?

Hello, I haven't run a 'successful' forum for a while. I think I sold my previous domain and community back in 2014. Now, I am looking at starting another niche forum, but really, I don't know how to go and promote it. I don't have the funds to dump into advertisers and such. And the issue is compounded because I am trying to make a forum that is very localized (for my state) and on top of that, the forum is dedicated to a newly legalized medicinal item. There could be a lot of potential for this niche area, but I don't know how to promote the site.

I have the site up and running, but really, lack the proper channels to get it out there. I have tried advertising on craigslist and such to no avail.

Any ideas?