Like abes said, No donations, you could make a donate function, but with no reward so they are donating to support the server and not for the items, also a bit high exp should be nice, but not to high, cuz that's fucking up the PvP. A custom map or high editted map is always nice. You should have some events like CTF and some custom and stuff. Also get GM's who are active helping the players and not who are not abusing their powers.
Basically this.
No donations, No trainers, Custom map, Decent quests, maybe custom vocations (IF THEY WORK - I've played to many servers with custom vocations that just don't work), well thought out map and monster spawns eg. no putting dragons next to town so there "Easy to get to".
Make it adventure"ish", no level doors, you remember like how tibia USE to be? You would go down a hole and not know wth was down it? Now there's a level door you now how a faint idea what's down there because of the level requirement on the door.
Make obvious quests told by NPCs, but also Hidden quests that no one knows about, perhaps put hints in books around the world, like quests that are ontop of everyones nose but hidden under something like a fire field or a cracked hole you can only open with a pick..
blah blah blah etc etc xD
I could probably write a book.
Problem with these types of servers, is no one plays them, there are a decent amount of full on RPG players, but when one comes out no one plays it or it ends up never coming out of beta, i've known and played afew OTs, that were amazing but never got out of closed Beta, weither it being the owner just giving up on it, it taking to long or the owner just doesn't have the time, because there not something that can be knocked up in a day like a RLmap with afew quests they actually take some time, dedication actual skill to make/design.