get a drill, a glass drill bit, some masking tape, and a water bottle to apply a slow drizzle of water. put a few layers all the way around the area you wanna drill the hole and turn on the drill drill through the masking tape and stop, pick up the water bottle and start a slow drizzle (being careful to not get it on the drill it's self, but the water helps reduce friction and in turn decreases the chances of breaking) and start driling, take it slow, the faster you go the more chances it breaks....good luck...