Drill holes accurately and without fraying

Again and again it happens when drilling in wall or ceiling: The drill slips a little sideways, the hole is not formed exactly at the mark, and the hole often frits ugly and must be refinished.

My remedy:

A small wooden board that fits well in the hand with wood holes in the diameter of the usual stone drills.

Before drilling in stone, I put the board with the appropriate hole on the marker and hold it with one hand. The other is then drilled with the drill.

It will drill holes exactly where marked and the plaster around the hole will not flake off.