Wear safety glasses and gloves
Mark the drilling spot with a permanent marker
Place the glass on a flat, stable surface
Support the glass with a scrap piece of wood or rubber mat
Use a diamond or carbide glass drill bit
Apply masking tape over the drilling spot
Keep the drill set to low speed
Hold the drill at a 90-degree angle
Start with very light pressure
Keep the drill bit and glass wet with water
Drill slowly and steadily
Pause often to prevent overheating
Reduce pressure as the bit breaks through
Stop immediately if the glass cracks
Smooth the hole edges if needed with fine sandpaper or a diamond file