Best sources of advice really depends on the specific situations. If its a problem with the customer I would speak directly with them to work it out. If the situation is over pricing I may call a friendly competitor to see how they might handle it. If the problem is a personal issue I would go directly to their supervisor here and get their read on the situation. If the situation is about collections I might ask a collection agency for advice or refer delinquent client to them. Each concern/situation would point me in another direction for advice. 

But for all round general advice from a common sense and fresh perspective I can always count on my wife for her unbiased opinion being a new way for me to frame the problem.