Ask VCs to tell you "NO"
Rick Segal wrote a post a couple of days ago about entrepreneurs misunderstanding VC's intentions. I found that most VCs are quite flattering with compliments and will rarely give entrepreneurs a flat out "No." Usually, the VCs say they would be interested if certain milestones are met and they nearly always offer to keep in touch. I don't blame VCs for taking this approach. Why wouldn't they want to invest if the entrepreneur hits the milestones they are looking for? I found knowing what the VC felt were important milestones to be helpful and one of my goals in meeting with investors became setting the stage for milestones I felt that I could hit. That said, it is clear that most entrepreneurs are overly optimistic and misinterpret these statements as signs of actual interest.
I think the best way to gauge a VC's interest is by their actions. Some basic signals include whether or not they respond to your email and if yes, how quickly? Do they want more information? Are they willing to take additional meetings? Do they want to speak with a customer? Better signs of interest would be their willingness to introduce you to people they know and getting partners involved.
Asking a VC what immediate next steps they would like to pursue is a pretty good proxy for asking them to tell you "no" and is probably something that should become a standard part of investor pitches. If a VC doesn't have any immediate next steps in mind, don't hold your breath.