Running a startup puts a ton of responsibilities on your plate. From marketing to sales, ghetto-HR to accounting, development to project management, you’re wearing a million hats.
CustDev interviews should be divided in 3 parts – People, Problems, and Your Solution.
Find customer pain and a solution they desire and will pay for. Rinse. Repeat.

Your goal is to not lead them to your problem. The less you lead them while still hearing your problem being mentioned the more validation you have!