Well first you should consider building a spawn, this is where you should put all your rules on display so players will know the rules from the start. Next you should build a shop, supply items that are hard to find but dont supply lava, flint and steel, bedrock or obsidian due to trolling. You should also build a hotel for noobs to live in whal they get started (note this should only be built if the server is survival) but dont let them live in it for too long. And finaly you should build rooms for the admins.