make server unique like:
no old weapons, only custom weapons from No-Grade to S grade.
no old armors, only custom armors from No-Grade to S grade.
make that accesories give some stats, like +500hp or cp or others stats.
make safe +7, max 30, normal 80%, blessed 87%.
make server no lagg, get a good protection [anti cheating]
get a nice developers.
make donations, but not make donars OP, give them items same reward as normal player can get.
make lots of auto events, like TVT, CFT, and others.
make event hold by GM, like LMS, 1x1-9x9, tournaments, trivia, HnS, and more.
make a nice website.
register your server at hopzone, gamesite, extremetop etc etc.
make a nice lvling zone, where u cant get pked by another player.
make a good farming zone [not too booring].