There is a more advanced method of acid etching as well that uses a non-diluted straight acid and more advanced stencils, but I do not recommend this method to anyone other than professionals who plan to do this for more than just a hobby. Acid etching of this sort is an advanced process used by professional artisans to create glass carving as well as surface etching. This method of deep abrasion produces three dimensional surfaces and an extensive knowledge of glass and its properties is required in order to produce structurally sound glass art - besides the obvious safety concerns.
Another professional method is sandblasting glass. This is the more expensive method due to the equipment involved, and the knowledge required to create this way.
Sandblasting produces the most consistent and visually perfect etched glass. It is a similar process to the cream method described previously in that a heavy duty vinyl stencil is applied to the glass and all other areas are masked off to prevent accidental abrasion. Super-fine cutting sand of different grits is then loaded into an air-powered sand sprayer and then sprayed at the stencil to abrade the exposed glass areas.