"What kind of economical structure do you have planned for this totalitarian regime? Before I sign on, I'd like to know you aren't just gonna use tax dollars to build a doomsday machine or death star. I'd be okay with supporting a bureaucracy that supports your rule because it promotes job growth."
Essentially, you have the nation divided into districts. Each one has a "Deputy" who is in charge of administering tax collection. The king will demand a certain payment from each district varying on population. The deputy will be in charge of making sure the right amount of money is taken from the people, and he will of course keep some for himself. Certain laws will then ensure that the money taken is a feasable amount, and is used for governmental projects.
When the money rolls into me, I will use it as I please. During our first years of growth, I will use it on military spending and developing nuclear arms. Once we have amassed a sufficient force, the money will be spent on making the citizens' lives easier until they are happy enough to willingly pay fifty percent of their income. (If they don't want to, then I got one hell of a military to force them into doing so.) Afterwards, all money will be spent on space research, building up the military, and the tremendous amount that must be spent on our industry. (Fascist industry is the most effective!) And of course, a great deal of money will be spent on the first couple of wars that we start. First against the E.U. because we need to take back the fatherland! Next, on America so we can show them who's boss. And finally global domination.