Step 1: Select your window glass. These happen to be from an old home nearby that was renovating to more energy efficient windows. It is a good idea to give the glass a quick basic cleaning before you start cutting so your cutting wheel doesn't get tripped up on dirt. Goo Gone will take care of any yucky black tar that remains on the glass before you start cutting if you happen to have this kind of window.
Step 2: Design your pendant shape.
In this design method, the drawing that you create to decorate your pendant should be in black and white, drawn with either a felt tip pen, or you can use your photo editing program to create a black and white image. Photographic details will turn out well if the image is converted to a high contrast black and white image (grey scale won't work as well). Scan your artwork into your computer. Print your pendant onto plain paper. * Remember that if you are using text in your image, you may want to reverse your image using your photo editing program before printing (a friendly reminder from "Wombatmorrison"). Cut out your pendant shape from the sheet of paper to create your pendant template.
Using your glass cutter, cut out a section of glass from your window that is large enough to cut out two layers of identical sized pendant templates.
Step 3: Trace your paper pendant template with a permanent ink pen onto the piece of window glass, TWICE.
Step 4: Use your glass cutter to score, then break the glass pendant shapes from your piece of glass.
Step 5: If necessary, use a glass grinder, or glass/concrete wet/dry sandpaper blocks to smooth and shape the edges until your two pieces of glass are the same size and shape.
Clean your window glass using plain liquid dish soap and warm water, or basic glass cleaner (don't use scented, lotion added products). Dry your pendant glass shapes with a clean dish towel. Once it has been cleaned, try not to get fingerprints on it :)