Shortly after I was first promoted into sales management, I was told by a VP that the most important element of my job was my ability to hire. And attracting the best candidates requires real strategy. It made perfect sense, for as my revenue targets continued to skyrocket, it became increasingly difficult to inspect any specific deal. I was left to delegate, and ultimately trust, my sales reps to provide accurate forecasts, close business, and represent our company in the best manner possible.

My first hire, "Jerry," seemed to embody exactly what I was looking for. His interview style was both commanding and professional. He was articulate with his reasons for joining the company, and his résumé was rich with consistent quota achievement and accolades at his previous jobs. And his 10-plus years of experience selling in our space convinced me that his learning curve should be short. Three reference-checks later, I offered Jerry a job.

Jerry proved to be the worst hire of my management career.

The challenge in hiring salespeople is that they are often excellent interviewers. They can be confident, persuasive, and engaging. Jerry was all of these things, plus he had tons of industry experience. But after many of his sales calls ended with Jerry arguing his technical opinion with our customers, I had to realize I had made a mistake. Six painful months (and dozens of squandered opportunities later), I showed Jerry the door.

Here's what you need to ask a potential hire to get the best person for your time:

Check their intellectual curiosity.

A salesperson must possess a presence in order to facilitate an executive-level discussion. The challenge is that few sales reps come to the job with deep technical or business knowledge. To ask them to appear credible in the eyes of a CTO or CFO can be difficult. So I prefer that the salesperson is comfortable adopting the role of "student" when in front of customers. Can he or she be confident while being curious? Ultimately, it is the ability to truly listen and connect with customers that sets the tone for the relationship. If you want to be interesting, be interested.

At the interview: Ask your candidate to persuade you why you should read a particular book or article that he or she has recently enjoyed. Here, candidates can showcase what they find interesting, as well as their ability to sell you on why you would find it relevant to your world. And don't surprise candidates with this question at the interview. True, it is great if they can think on their feet, but I also value a salesperson who can thoughtfully prepare for a sales call.  

Ask them to show you hard numbers.

Winning is often a habit. Unfortunately, so is losing. When someone has a history of setting and achieving goals, the person generally is also persistent, resourceful, and optimistic. And this evidence of achievement shouldn't be limited to selling. Has the candidate enjoyed achievement personally? Academically? When the candidate begins an endeavor, does he or she expect success? Does the person, to quote the late Dr. Stephen Covey, "begin with the end in mind?"

At the interview: Ask the candidate to provide specific numbers to illustrate his or her professional journey. Did the person secure a competitive seat with a music company or sports team? What was the candidate's GPA and class stack ranking? Exactly where was his or her performance to quota achievement in relationship to overall sales org? It isn’t just the numbers that impress. It is the specificity of numbers. People who achieve generally know these numbers cold, because they use numbers as both beacon and barometer.

Get a customer reference.

At the end of the day, the one skill that sets great salespeople apart is the ability to close: namely, to inspire a customer to make a decision. Although closing techniques can be both taught and refined, the appetite to close is a specific character trait. Either you like to close or you don't.

At the interview: Anyone can offer you names of previous colleagues and employers to sing his or her praises. But isn’t it the customer who knows best? Ask your candidate to provide two to three customer references. Then, ask the reference how the salesperson was able to navigate the organization, handle objections and roadblocks, and ultimately secure the sale. With little incentive to embellish, the customer reference can provide terrific insight into the candidate's sales and closing skills.

No single question in a one-hour interview can predict the success of any individual sales hire. But at least these three elements may prevent the next "Jerry" from joining your company.