I also included basic instructions for custom stenciling, just in case...
So, while the manufacturer recommends glass etching products for stencils it's possible to use it like paint. The wine glasses I did last year were hugely popular, so I hope these are a success too.
Step 1: Gather materials and tools
1 jar of Armour Etch (from most craft stores, possibly from a hardware store?)
1 (or more) glasses or any object made out of glass
And since etching cream is really nasty and caustic:
1 pair of gloves
If you want to stencil your design you'll want some vinyl contact paper. Make sure it's sticky enough, but even then you may have trouble getting it to cling to a rounded surface. You can also use plastic stickers to create a 'negative' image, e.g., a frosted glass with non-frosted polka dots.
This is a project for adults, in fact, you have to have an ID to even BUY this stuff.
Your product might be different from mine, so read all of the directions that come with it!