Just make sure you have enough trusted “lieutenants” to be your subgovernors/government ministers/whatever. And there’s always going to be Collaborators in whatever society you take over. Heck, and if I’m able to start implementing some of my more “benevolent” policies (Such as bringing peace-and food, and medicine-to Africa), there might even be large numbers of “the people” who would gleefully SUPPORT my reign over them. Especially the people in the, how shall I say, “Crappy, Destitute, Famine Ridden” sections of the world.
And as for corruption? Some is to be expected, if not condoned. And how to deal with it? A series of internal checks and balances. And purges. Violent, bloody, purges.
Massively unequal retaliation would be a way of keeping rebellion down, too. IRA splinter group attacks one of my government offices? Drop a 50 megaton nuke on Belfast. And Dublin. And Cork. Impose a 10 year blockade on Ireland, napalm the crop fields, and Anthrax the livestock. “Anyone ELSE want a piece of me?”
Lord Regent Ranchoth
(“A head for an eye, a hand for a tooth.”)