First I got these beer mugs at the dollar store (awesome right) they are not the type of glass you would usly see at the dollarstore so I bought them all, twice.
I still can't get over how nice and heavy they are, Clean them up remove all lables.
Design your stencil in your prefered software I used the inspiration pro....love it. Make sure you add a square around you design for proper placement on the glass and as not to get etching cream all over the glass. (Tip) use a font that conects all the little small inside pieces of your letters it will save you alot of headaches later.
I made my stencil out of contact paper or some people call it shelfpaper much cheeper than vinyl, I didnt even use a whole roll for all my mugs and a roll was 5 bucks at home depot.
Cut your stencil on the Best Machine in the world Pazzles Inspiration. Ok I guess you could use other machines but not in my house.
Now heres the trick remove all the positive pieces and leave just the negitive outline.
Then add your stencil to your mug, some people use transfer tape I don't, I just find it easier. Carefully rub your fingers around every part of your design to make sure you do not have places for you etching cream to sneek under the stencil, because it will.
Dab Armour Etch or what ever etching cream you choose on the exposed glass making sure to keep it within you stencil area.