Ask HN: What is your best customer development tip, trick, hack?

If it is early on, do a needs analysis call separately from the demo by a week or so. In that time and if the lead qualifies as worthwhile (adding 1+ months to runway), build whatever extra feature or screen they mentioned needing but you know you do not offer. Or three if such is the case. And then give them something that meets their need 100% during the demo and try to close them then.

Here's one:

Never show your user/client any visible disappointment when they change requirements. In fact, give them the license to change their minds aggressively.

Go at the hanging boxing bag later at home.

Find a client or two who can become your subject matter experts in exchange for early access / beta releases. They'll validate it and know your market. so similar clients will meet the fit