It is evident that wrong hire of resources cost the organisation heavily if resource(s) failed to connect and align to the organisation process and similarly the cost can be huge if it is a wrong hire of business development/ sales professional(s) as it puts the organisation revenue growth behind many years. So how one can evaluate a successful sales professional on his ability to deliver the results.
Monitor Your KPI over a set period of time and try to control some variables like availability of operational tools and motivation
Before figuring out whether or not they'll be able to generate results I think you need to focus on whether or not they fit your company's core values. Otherwise the results won't last or they will conflict with your core Focus.
My first reaction to this comment is to say understanding the difference between a Business Developer and a Sales Person. As a Business Developer myself, this is quite sensible for me.
On another note, I would go for an experienced background with past results that you can evaluate. No need for it to be in the same industry. Even though past results don't ensure future success, it remains a good indicator. I would add that a "nimble" mindset is important. Someone that understand that our current ecosystem requires more than cold calling and emailing. Someone who is able to leverage all the new technologies out there for lead generation and sales.
Hope this helps!
Rajesh, you must select a senior sales partner to not only execute sales on your behalf, but develop new methods of differentiating your unique capabilities. You would be best served to recruit people that can execute direct selling campaigns, social and digital sales, and BD functions. As you interview candidates, define a broad set of sales KPI's you want the person to achieve and ask for a detailed sales plan back from them within 3-4 days. You will benefit by comparing sales approaches and select the plan you believe you both can execute.