There are many tools available to help write a mission or vision statement, but I think it's often best to keep it simple -- one or two sentences -- and describe why the business exists. What is the core value or the daily purpose? Write it down and share it with everyone! Next, create an employee manual that reflects the culture.
Source: Six Keys to Running a Successful Business: http://www.inc.com/gems/blog/2007/11/six_keys_to_running_a_successf.html
Contributed by: ~C4Chaos