*cough* I'm a nerd.
In order to do /t add, you have to be a recruiter, assistant, co-mayor, or mayor.
You also need residents. I'm not sure of the number of plots each resident you add allows, but I think it's 8.
Joining a nation (just ask in /w for a nation and /accept) will give you a plot bonus of 140. Most nations do not have tax, but there are some that do. If you join a taxing nation, be sure to have enough money in your town/personal bank.