I have recently started some work based upon my shifts working at the local pub. Regulars are often more recognizable by what they drink, rather than by name - so I'm creating characters based on their drink of choice (fitting the text into the specific glass shape).
Taking sketches of punters drinks - I put them on top of a light box. And then cut out the text in the shape of the drink, which can be painstaking - but I am left with tiny confetti-like letters covering the desk...
Layering various pieces of paper on top of the light box - you can see through to each layer.