Trimmed/Molded Cabinets
In the case there is trim, like in new cabinets, they are centered bother horizontally and vertically in the trim, but still diagonal from the corners. (unpainted usually)
Top Cabinets
Typically we do 2 inches diagonal from the bottom corner of top cabinet doors
Drawers
Center vertically and horizontally of drawers, except false drawers under sink,
Bottom Cabinets
Top diagonal from corner 2 inches of bottom cabinet doors.