It's a Matter of A Minion
Handling Henchmen is a perpetual and pernicious duty. What follows are some general tips to make the odious task more palatable.
Learn Their Names
Referring to them by serial number feels powerful, but calling a man "Bob," when you order him to kill a prisoner increases that henchman's morale and improves his loyalty to you.
Pay Them
Never underestimate the power of the almighty dollar. A hefty bonus now and again will keep them coming back for more. If you have a robust commissary in your lair, feel free to pay them in scrip. If it was good enough for Robber Barons, it's good enough for you.
Add a Suggestion Box
Utterly meaningless, and it will give them a sense of control.