If you do metal engraving, get a cutter sharpener.
I only use outdoor material, so I stock only the expensive material. Double stock is a killer.
Plastic engraving is very profitable.
Custom engraving is not for the faint of heart.
Have a full array of cutter tip sizes.
Set up standards for standard sizes; for example, 1-by-3-inch tags, name badges, plaques, etc.
Save your work and print out job copies.
If you’re busy enough, have more than one engraver and schedule things you can do while the machine engraves. One person can run four to five engravers or other machines.