Tips for client reach out

I'm reading Monetising Innovation and one of the tips is to speak to customers early.

"Have the “willingness-to-pay” talk early: To find out the price customers are willing to pay for a product, companies have to talk to them."

What are some people's tips for having these calls? I'd love to speak to CTOs of different companies although many will be too busy to take a call if they don't have anything to gain from it themselves.