Talk about a tough crowd. When the National Speakers Association selects speakers for its annual conference, held this year from July 17-20 in Phoenix, it has to impress a particularly discerning audience — the 3,500 professional speakers who make up the delegation.

So what does the National Speakers Association look for? “Expertise and eloquence,” says Mark Sanborn, president of the NSA. “We don't just want a speaker with great platform skills, but also expertise and ideas that will directly benefit our members.”

This year a key objective was to showcase diversity in speaking styles and subjects. The lineup reflects that with Terry Savage, a personal finance expert; Seth Godin, a columnist for Fast Company; Larry Winget, “the pit-bull of personal development”; and Joe Calloway, a branding authority.