Your team has a good project, one you believe in and which will help your organization to achieve its goals. The next step is to write a good vision statement. You may think that everyone understands where the project is going, but folks are probably more confused than you think.
Here’s Scott Berkun on the subject, from The Art of Project Management:
Because everything derives from the high-level vision, the team’s overall leader should invest more entergy in it than any other early planning material. The five most important characteristics [of a good vision] are:
I counsel my students to write short vision statements, no more than a sentence or two. The language should be vivid and exciting, quickly communicating that vision of the future state which gives their project meaning.