Locate elevators in sight of managers office if possible. Design adequate space in front of elevator to allow waiting and passage.

Images and Captions:

The elevators in this San Francisco apartment building (highlighted) are centrally located and open onto a generous waiting area on each floor. 
(555 Ellis Street)

The elevators in this Seattle development (highlighted in red) are located close to the manager's office (also highlighted in yellow). 
(Cascade Court)