A good project board (or innovation steering group) is valuable asset that should last a lifetime if you look after it. So treat it with respect, put effort into maintaining relationships. Innovation needs guidance, maintain your board with a variety of members with different viewpoints and experience. This will help ensure you get both the right critique and the right insights from all angles. Regularly Wax (lyrical) to them about progress in your current innovation projects.
For an overview of ‘Rules for Riders’ see previous post
