You could write a full book to answer this question. We've had great success hiring sales team members from other businesses in the same industry as our own. It helps to hire sales team members who've sold different services (or goods) to a similar clientele. This way, they come into the gig talking the talk - and knowing about industry expectations, vocab, best practices, etc.

Comp package will dictate the caliber of candidate you can attract to the position. I've always found our best sales people to be folks who work for only a limited commission (ie: 20% - 35% of their overall earnings) and a competitive fixed compensation.