Hole punching in metal

In the “and other duties as assigned” bit of my job, I had to punch a two-inch hole in a steel cabinet for cords. Here are things I’ve learned:

Go slow. Slow and steady wins the race. If you feel your drill fighting you, slow down. You’re working together!
Make sure you have a hole saw that can cut through steel. The hole saw kits you get at the home center are good for wood, PVC, and perhaps light aluminium. They’d never stand a chance through steel.
When you’re finished, protect the cut edges of the new hole you’ve created with electrical tape.