The "Toyota Way" as documented in Toyota Motor Corporation Annual Report, 2003, and by University of Michigan professor Jeffery Liker (2004) has at its core the '4 P's' of 'Philosophy, Process, People/Partners and Problem Solving.'

These 4 P's are also the essential components of Lean Six Sigma and a good way to remember what the essence of Lean Six Sigma is all about.
The 4 P's  are a good learning tool for new students of Lean Six Sigma.
They are just as applicable to business improvement in Service as in Manufacturing.  See the above diagram.   I have attempted to include all the essential components of Lean Six Sigma in the above diagram although this, of course, is not a fully comprehensive list of all Lean Six Sigma tools and techniques.