Why are you building this product, providing this service, or starting this company? If you can't answer these questions, ask yourself this one; are all your teams working towards the same outcome?
While it may seem naff, cliched or even trite, you should be creating a simple Vision Statement for every major product or project you undertake. This is a short description of the better future that you are all working towards. Simply defined, a good vision statement should be: