If you want your server to be formed off of a certain topic, to have neater builds, less builds, and less lag, try these suggestions!
Formed off certain stuff/neater builds
You can say in the welcome message, “If you would like to build you can buy a plot, but first tell me what you are going to build, and be honest.” Also, set world modifications to admins only. This can help neaten up a server.
If you already have a messy server that you are dissatisfied with, put on a password, and just take some time to make it look nice. This way, if you have to remove, or just move some builds, the builder won’t see and get mad.
If you own the server, all you have to do is steal the animals. Yes. Steal. I know it sounds mean, but if it’s lagging, that’s likely the reason. Also, get rid of any farms, and non-solid blocks. This includes, trees, plants, water, and trade portals. If your server is very large, simply put a trade portal every few hundred blocks. Do the same with portals, chests, and safes.
That’s all I have. If you need any other tips for servers, just say so, and I will create a topic.