One question when doing your Mission - How are you going to win in this game?

Business owners needing to push their people more in a shared direction look to the Mission statement. Yet, when I am working with companies, I meet many owners who believe the Mission is a description only, not an aspirational dream. They also stick to the safe words and descriptions - "we find world class solutions for our customers." So what? That is what everyone is doing. If your Mission is the same as any business in your industry, tear it up and start again with your senior team. Make sure you put in a financial goal too.
I have followed Jack Welch's principles of strategy for twenty years and I think his definition of the Mission is the best I have seen. By the way, good Private equity firms  know how to use the Mission statement. Make sure you ask about their expertise in using them.
Jack Welch believes that: 

An effective mission statement basically answers one question: How do we intend to win in this business? 

It does not answer: What did we used to be good at in the good old days? Nor does it answer: How can we describe our business so that no particular unit or division or senior executive gets pissed off? Instead, the question “How do we intend to win in this business?” is defining. It requires companies to make choices about people, investments, and other resources, and prevents them from falling into the common mission trap of asserting they will be all things to all people at all times. The question forces companies to delineate their strengths and weaknesses and assess where they can profitably play in the competitive landscape. 

Yes, profitably – that’s the key. Even Ben & Jerry’s, the crunchy-granola, hippy, save-the-world ice cream company based in Vermont, has “profitable growth and increased value for stakeholders” as one of the elements of its three-part mission statement because its executives know that without financial success, all the social goals in the world don’t have a chance.Now, that’s not saying a mission shouldn’t be bold or aspirational. Ben & Jerry’s, for instance, wants to sell “all-natural and euphoric concoctions” and “improve the quality of life locally, nationally and internationally.” That kind of language is great in that it absolutely has the power to excite people and motivate them to stretch.
At the end of the day, effective mission statements balance the possible and the impossible. They give people a clear sense of the direction to profitability and the inspiration to feel they are part of something big and important.
Read more of Jack Welch's views and Suzie Welch.