What I usually do is offer different stuff from the usual servers, of course: if you're selling yourself, you'll need to do it like a peacock, show your feathers! I usually too call EVERYONE from my Steam to join the server and, in order to do this, I give a few rewards for the first joiners, such as some money or some other benefits which the gamemode might be able to offer; a lot of attention from your staff is required to the new players, so they get along well and understand everything the server may offer! Some modifications to the usual HUD or other stuffs that comes as standard from the gamemode might give a different look to your server - even if you don't have any, really. In my opinion, a friendly staff is the most important part of a server; and if you can cativate the playerbase by making them feeling themselves somehow important, they will stick with you loyally.