screenprinters: I may be stating the obvious here but...

[runmikeyrun]

...when i set up my artwork for the screen i always include a small crosshair where the center of each of my pots, switches, leds, etc will be.  Then when i screen the enclosure i know exactly where to drill so my pot/switch is right in the middle of my graphic. 

[jjucius]

good idea, that would save a lot of time lining it all up

[Dave_B]

A similar trick I'm trying: If your LED's/Switches/etc. are board mounted and you're creating your graphics in Photoshop (or whatever), import the board artwork to make sure the scary LED eyes line up ok.

Example: