Get some etching cream. They didn't have this at my craft store, so I was going to get some from amazon; but my mom had some in her craft supplies, so I stole it.
You can use an exacto knife or scissors to make the pattern you want to etch. Remember to make a negative of the design that you want. Whatever is covered will be clear, whatever is uncovered will be etched. Use contact paper so it sticks to your glass. Paint on the etching cream and wait 5 minutes, peel off the paper and rinse with water.
Tonight I'm going to etch the words "cream" and "sugar" onto some jars I got for our coffee station at church. I'll post pics if they turn out well :)
>>>Here are the jars I etched for church. I'm pretty pleased with them!