You need to set near-term milestones. Put the assumptions down on paper, and make it to your vision or ultimate product. Your team has to understand where they're going. Your partners need to understand where they're going.
There are a lot of designers who think they understand technology and a lot of technology guys who think they understand design. But to put them together and make it robust and repeatable for the mass market? It's an art.
Every team member who brings intelligence, experience and passion to their creations should be called an artist or designer.