How To Sell Professional Services to Businesses. An interview with entrepreneur and intellectual property attorney Bradley J. Gross. During this sales training video Dave Lorenzo and Brad Gross discuss how to sell professional services. During the past ten years, Brad has employed professional speaking and nice marketing to grow his personal brad and develop a massive book of business. In this interview you will discover the four keys to selling services. They are: Personal Learn more about your ad choices. Visit megaphone.fm/adchoices