Can I raise the local taxes on my subjects?
First, you need subjects. Build a trailer park, and advertise, mostly to retirees with a little money to kick around. When younger folks come along, they'll need jobs so you create a little infrastructure and hopefully your tax base will grow. You own the land, have them build the structures. I don't know if they'll long tolerate you being king unless you're very kind to your subjects or you have good security.