I've been working in OD as a consultant for almost 9 years. One think that I learned is that, sometimes, what your client say, or ask for, is not what he wants or what he needs. More than one time I had to think what my client was realy asking me, what he was trying to say with those words. The problems is: if you make your proposal without considering this, maybe you will not fulfill his real needs and consequently not succedd as a consultant. My sugestion is to develop your perception and compreention skills. One book that explain how organizations work, regarding this issue, is "Removing Barriers to Change"The Unwritten Rules of the Game" by Peter B. Scott-Morgan.
I hope I have been helpful in some way. Good luck!
Carla de Souza
salubrit@nutecnet.com.br