I'd start with *Nail it, Then Scale It*. Specifically for customer development, ...

badclient on March 30, 2012 | parent | context | favorite | on: Steve Blank hands a new owner's manual to startup ...

I'd start with Nail it, Then Scale It.

Specifically for customer development, I'd check out The Entrepreneur's Guide to Customer Development: A cheat sheet to The Four Steps to the Epiphany.