How can I maintain the loyalty of my evil minions?

I've just had a number of my minions leave my evil organisation due to their low loyalty to me.

Why does this become low, and what can I do to increase it?

Losing Loyalty

• Body bags have an AoE that reduces minion loyalty.
• Overwork without recreation reduces loyalty.
• Minions with low attention can accidentally trigger traps. This can cause loss of loyalty depending on the trap.

Regaining Loyalty

• Your avatar has an AoE that inspires loyalty. Make sure you always idle in a well-defended but minion-rich room such as the Control Room.
• Loot items have an AoE that increase loyalty. Place these in areas where your minions concentrate (control room, barracks, etc).
• Torturing an enemy agent (or another minion) will increase the loyalty of those who witness the act.
• Access to a Staff Room with appropriate equipment will keep a minion loyal.
• If you see someone deserting, you can capture them and throw them in a cell for a few minutes. They will become very loyal again.
• You can execute a minion to make those who witness the act very loyal.