I can definitely second the book recommendation. To elaborate a bit, one of the core ideas of the book is to avoid leading your customers by telling them what

I can definitely second the book recommendation. To elaborate a bit, one of the core ideas of the book is to avoid leading your customers by telling them what you're planning to do (which they invariably respond to with "that's awesome!"), and rather get them to reveal their real problems. This allows you to make sure your product is aimed at the real problems. Another great skill is to understand the "commerce" of various interactions and commitments. Getting a "that's great, send me a mail when you guys are finished" sounds wonderful, but is actually "leave me alone, I'm busy". How to gauge the potential client's level of interest, and to actually seal various levels of commitment from them was a real eye opener.