Well, I linked it on Facebook. To all of my forty friends. >_> Generally, servers rely more upon some auxiliary source of players. The whole "Mount the Frak Up!" directive is pulling, but it's not enough. Existing communities or content websites(like Press X or Die or RPS) typically keep these things alive. Then there are factors like player slots, map rotation, rules and so forth. For example: I don't want to play on a non-hardcore server(do they have hardcore mode?), and I don't want small maps. So I will avoid servers that don't provide what I'm seeking in a game of BF3.
Heck, even culling an established community doesn't promise server popularity. It certainly helps, though, and that's where I would start. Let a mod or admin correct me if I'm wrong, but you could always start a dedicated thread to your dedicated server with information, screens and promotional jibber-jabber.
And for fuck's sake: police the server. Just don't over-police it. A fine line between maintaining traffic and booting slut-potatoes.