Consider the role this position will play in your company. Since you will get any new hire "as is", you want to ask questions that help you determine if the individual is the best candidate for the role the position plays. Be clear about what will be expected of this position, measuring candidates against the role helps you find a better match without confusing the decision with unnecessary information.
Look for special skills that will improve results produced if hired. Go beyond obvious requirements of the position and ask about experiences that can contribute beyond the hired position. Ask questions that explore improving the value of the position should this individual be hired.
Discover how this position aligns with their stated career goals. Ask where the person sees themselves in 5 years, but go one step further, ask why they see that picture and how they plan to reach that point. Don't accept generic answers, demand detail as it pertains to matching an position to an individual. Great candidates would have shared these visions with the people around them, so it's okay to ask candidates this too.
Learn how flexible the individual has been in the past with adversity. Take time to explore past failures, ask questions about how the individual recovered, what obstacles they overcame, and how did they enlist the help of others. If someone hasn't had any failures, perhaps they aren't trying hard enough. Look for consistency in events between candidate and references-- ask for references close to the event if possible.
Consider how many people would follow this leader to another company. Explore the individuals sphere of influence to discover other resources this individual can bring to the aide of your company. Ask about resources your company currently needs, explore channels of mutual benefit. (This isn't a measure of how many customers they will bring, but actual strategic partners.)
Learn about their ability to cultivate new talent. Ask about the candidates successful team members whom they mentored to solid achievements. It's important to have quality relationship builders on your team for long-term success. Hire people who embrace younger talent and have the ability to share their own knowledge.
Understand this individuals ability to learn. Seek details about any changes in mind-set or times when the candidate had to look at something differently to achieve their desired results. The flexible people you want on your team are willing and able to learn what is necessary to keep up with changing customer demands. Look for candidates who participate in self-study or a personal learning program.
Be weary of overly positive comments. When you hear overly positive remarks about a candidate, consider why would a company give up someone with such talent. Look for more details behind general comments by asking why someone feels a certain way, or what specific event contributed to that opinion. You'll gain a better perspective on the comment and less likely be unintentionally mislead.
Seek to understand the sphere of relationship influence this new hire may have. Go beyond their ability to bring new resources to you company, but look at their strengths in the area of cultivating employee and customer relationships. If possible interview their subordinates to find out what kind of a supervisor they are-- even for nonsupervisory positions. You need people who can enhance the strengths of those around them.