Running group survival servers is tough, the competition is massive. But it's not impossible. Here's some advice;
- Try to get a plugin setup that is different, look through the plugin list on bukkit for obscure plugins that will interest players.
- Get a plugin developer to code a new plugin for you, it's not that expensive, and makes your server unique.
- Make colorful banners and images of your server.
- Post everywhere, the best tactic is to google "minecraft servers" and put your server on every server list site that comes up.
- Make a server twitter account, facebook or even google+ and share it with your real life friends, odds are some of them play Minecraft.
- Have an online forum or website, you can get free forums from forumotion and website hosting from moonfruit.
- Bump your posts every day.
- Get Votifier set up, ensure players are rewarded for voting, and make sure they know how to do it
- Build an epic, yet simple spawn. Something that will make players think you have put effort into your server.
- Get a good staff team. You don't just want people to moderate, you need people who will help you run the server, people to manage your website, build for you, manage your plugins. Ensure they are mature, and friendly.
- DONT use factions or towny. They are dull and repetetive after a while, get something different like Kingdoms set up.
- Give players goals. An achievements list is great, also a ranking system.
- Don't give up. The longer your server is up, the better it looks. A 2 year old server is much more appealing than a 2 week old one.
- Set up a donation shop straight away, I recommend enjin. The only way you will grow is with money.
- Don't just be the owner. Be a friend to your players.
Hopefully that should help you out.
~Evil