I had Robert Stapp of OP•EX Direct Results Inc. on the Business901 podcast and in part 2 of this podcast, we had a discussion on operational excellence. 
He discussed several ways to leverage Lean and Six Sigma in achieving excellence.
The lesson I learned from the podcast was that these were not the only tools he uses. He looks at other tools depending on the customer and their needs. Part of the discussion neared the “Best Practice” area but I thought his insight on the people rather than the tools were particularly helpful.