For me it's easy to answer...they come from another Christian forum. A lot of them have been banned from that larger Christian site and we are more lenient with our rules and want to work with the members to show them how we expect them to behave instead of just handing out staff actions automatically. As a small site it's working but if we grow to big then we'll have to change strategies.
Most of my members come from clan relations within-game and advertising through other forum communities.
My SEO isn't on-par because of a pending and much-needed SSL update, among other things such as a lack of backlinks. I also lack social media presence and other areas such as fresh content and my competition is very stiff. So, a lot to work on over the years, but I'm in no rush, it's all for fun at the end of the day.
Although staying on the topic about what is working, I'd also like to say my Discord server has been a good contributor as well.
For me most comes from other gaming-related sites and then here on FP. Rest from search engines but didn't get much as I thought. then again at times I#m not putting in the extra work. Then the lack of social media. Yep social media should be number one here on the list to do.