Checking that your server isn't dead.
Enabling only relevant or useful Add-Ons to a server. Mini-Nukes and whatever various generic machine guns you have usually are not useful in a pirate RPG server, unless you want to utterly break it.
Having a definitive theme, ruleset or original mod in the server. (e.g. if you're hosting an RPG then make your own RPG mod as it'll be guaranteed be much better and original than CityRP or the various event/Variables-based ones)