Hard work and a great memory are valuable criteria. I encountered two notables.
Air Cdre Cyclops Brown took over at CAW Manby, and didnt emerge for a week. The following Monday he knew the face/name of every officer and SNCO at Manby and Strubby.
AVM (as he was at the time) Mike Knight was doing his AOC 1 Gp Inspection at Waddington. In the Tower was a brand new WRAF Plt Off, arrived the previous week. He looked at her and said "Weren't you the station photographer at Machrihanish last year?" Sarah did have an impressive chest, which may have helped jog his memory.