Like the holy grail, interviewers are always looking for the characteristics in a candidate that will tell if the person can sell. Two that I particularly look for are 1) Social monitoring and 2) Control.
Social monitoring is much like empathy. It means the person has a good radar for how others are feeling and acting. When done well, it fits the definition of emotional intelligence. But for sales people, it primarily means that the seller is noticing his/her impact on the prospect and can make adjustments as needed. In NLP terms, it is the ability to take a 2nd position and see the interaction through the prospect's eyes by noticing what the person is doing or saying.
Control is seen in two ways. First, the individual tries to control the interview, whether it is with you or with a customer. Conversations are forced back on track and toward the seller's purpose. Second, once an order is received, the seller controls the process inside. He/she rides that order and sees that people process it quickly and accurately. Often, the seller is seen as an irritant by inside people due to this control, but most good sellers show this trait.