Elevator Theory 101: Ever notice some hotels have elevators that only service certain floors? Build more elevators for floors with something to do, and less for rooms, which can be the upper, upper floors.
Also, don't place your elevators next to each other. They only get impatient if they wait in line, but if they take lots of time to WALK to your elevator, they won't mind, giving the elevator time to de-congest.