Bill Waddell has written an excellent article on the "real world" of Lean, which has been posted on Superfactory. It is based on the thoughts of Shigeo Shingo, who was the "nuts and bolts" implementer of Lean, whereas Taichi Ohno and some of the other masters focused more on the theory.
The most interesting part of the article is the discussion on how your perspective can affect how you attempt to implement Lean. For example, a materials person will focus on kanban and inventory minimization, manufacturing engineers may focus on quick changeover, and quality engineers may focus on SPC tools. Shingo reminds you that you must know which tool to use for which situation.
The essential common denominator is that you must, in a very detailed manner, track every component from start to finish, looking for every waste at every step.