Well, I just created a new group, Persian-Jews (https://www.deviantart.com/persian-jews), and I've also created Zoroastrians (https://www.deviantart.com/zoroastrians) and Kurds (https://www.deviantart.com/kurds), none of which have any members.
LOL
However, there are a few things you can do to help advertise.
The first thing to do is post your club in the Projects forum. At least you'll get some pageviews there. The second thing is make sure you get listed in club listings, and not just one or two, all of them.
Another thing, affiliate with other clubs of similar interest :) Send them a note, and when you become affiliated, people will see that in the journal and will go to your club and theres a high probability of them joining since the t