One of the things we offer with our tanks is misting holes to make misting your reptiles easier. What this requires is drilling holes in the glass. That's a bit harder than it sounds.
Drilling into glass requires specialty drill-bits. Most of them have diamond encrusted heads, and these drill-bits do the work, not the force of the drill into said glass. It's also rather time consuming. You have to stay in relatively the same position for several minutes to make sure the hole and the cut are even. Starting the hole is the hardest part. Getting the circular cut established requires careful control so that the drill doesn't skip across the glass and leave ugly scratches.
I'm still not particularly wonderful at it, but practice makes perfect.