Obviously the normal things, Decent map (Detailed or not) it should be paced out properly, alot of mappers fail by putting dragon spawns etc so close to a town without thinking logically about the creature & hunting ground they are putting in.
Dragons are the perfect example, firstly understand the lore of a Dragon, it's feirce yet intelligent creature, it enjoys warm environments & solitude, it thinks of iteself as a higher being it does not pounce around random locations with goblins, drinking tea and cookies, on a typical sunday afternoon.
(Notice on rltibia, most dragons spawns are done beside some volcanic lair & away from any well crossed path or road, they're in dungeons etc)
People keep stupidly putting there dragons ontop of mountains near no volcanic enviroment or in open fields, wtf is a dragon doing there?
Has anyone ever ventured under thais & found the books that tell of the human expedition & the battle that is going on down there between the minotaurs & the orcs? Did you even know there was a story behind it down there?
A complete re-do of the current items in Tibia, not graphic wise, just stat wise, re-design them to fit your own setting, it gives your game a much more clean & unique setting of mystery, what's this items do? what does that item give?
Vocations & Spells - Personally i believe people should stop trying to change them or make new ones, the current ones we have for tibia, match tibia & changing them in anyway destroys all balance that currently exists. People make new vocations believeing it will make there server the shiznit but take no pvp/pve into consideration, yea some do, they test alittle but not enough to make sure, leading to serious flaws & imbalances that nobody likes.
If you're going to make custom spells or vocations, make sure you put extensive time aside to test them completely, in a PVP & PVE settings at multiple levels.
- People now keep thinking all there RPG server needs is some nifty system that sets it apart, or some nice custom vocations/Monsters/spells, but in my opinion this isn't the case, what makes an RPG server unique is the setting it is set in, the items you can find, the lore around the world that you're playing, the map being logically made, books, quests, the questions "Why are these amazons near this dragon cave? Are they hunting the dragons is there a quest connecting it?" not "Wtf amazons near dragon cave for no reason lulul"