will try and help a bit if I can out of experience with RP servers
1. Destruction of Land
This kinda gets annoying when you go out to the wilds wanting to build and you have to walk half way across the world cause it's a waist land and doesn't feel so RP like, so maybe make special areas for it? Such as a mining or tree farm area, and encourage replanting trees. Though people can still alter the wilds so they can build.
2. Warps/spawn are towns
When players first enter the server have a lobby were they select class, race, job ect. once they do they teleport to the Main city or their class/race area were they can build or buy their house if they want.
3. Shops
In each town have a variety of shops, and they don't have to exactly give an item they just add to the feel, let the players put some creativity into it, some examples are a baber shop, black smith with Farrier, Inn, and clothing shop as well as the basic stuff, try and think of what kind of shops your theme would have and maybe certain races sell certain item.
4. Custom mobs or monsters
Don't have to say much about this one it's kinda like custom NPC but you fight them.
5. Pay attention to detail
As I said with shops think of stuff that applys to your theme. One idea might be to add random structures around the world for people to explore (you might have to add protection so people don't mess them up but allow interaction).
6. Local chat that simulates talking
What I mean with this is make it to were you have to be near another player for them to hear you or if they are further away a yell command, also a whisper command if you want to tell a player something you don't want others to hear; you have to be right next to them do that.
7. Pet storage
Lastly the ability to summon/dismiss your pets, I saw a sever that did this and it could be very helpful so you don't lose your pets, some of the commands were: petclaim summon [mob name] [#] | petclaim stable [right click the pet you want to stable] | petclaim stableall | petclaim list. This was a custom plugin but you might be able to find something similar or make one if you can code.
Hope some of these ideas help , I was thinking about making my own server at one point but I sadly don't have the time. And dissregard the race stuff if you aren't adding races.
