Use chemicals to etch your design into your glass easily for that frosted look.
 

For maximum control, you can use an electric tool to actually carve designs into the surface of the glass using diamond bits!
 

Another way to permanently carve a design into the surface of glass is to blast it in using grit under pressure.
 

If you are going to etch or sand blast glass, you need to have a resist covering those areas that will remain clear. If you don't all you'll get is a big piece of frosted glass. Find rolls of uncut resist or pre-cut stencils for your etching & blasting needs.
 

Why settle for just an etched image when you can embellish even further!
 

Plenty of books, patterns & how-to packets to get you started on making etched, carved or blasted glass.