I agree with the comments by made by Celine regarding Critical Success Factors for Change Management.  I would add in addition that the role of the temporal team is to infiltrate the organization to create and drive small campaigns that lead to success.  This definitely ties into the concept of "chunking projects" or breaking them into small scopes versus trying to implement large scale changes.  Note I used the term temporal team which relates to those individuals who are responsible for driving and implementing the change.  My purpose in doing so is to ensure that as quickly as possible that the change is made operational or internalized as the common way of working versus held out there as some program which appears to be in addition to the way people work.  Yes the company must own it and they must be committed to making it work.  Therefore metrics and compensation need to be tied to its success.  If not then there may not be sufficient motivation to get it done or to want to make it work.  Learnings from past failures and current efforts also need to be captured and leveraged.  Like the expression goes "if you don't learn from history you are doomed to repeat it."  Most companies have attemped large scale changes before and there is a wealth or knowledge within the the corporate memory and people that can be harvested and should be employed to facilitate improved progress and results.  Finally I cannot stress enough the need for and meaning of engagement especially at the middle management level where many projects either succeed or fail and with the individuals that have to work in the new world.  Many companies default to communications plans but this is not sufficient to make change succeed.  You have to rewire the organization and this means creating new norms, teams, relationships, ways or working, etc.  Knowing who the change agents in the organization are and also understanding the issues of change that traverse the organization in advance and programatically performing interventions (town halls, team building, walk throughs or pilots, feedback sessions, compliance and consequence management, etc.)  throughout the change are imperative.  I draw these experiences from 30 years of working in IBM where for the last 15 years I was part of the Global IBM Business Consulting Organization where my work entailed leading major international Transformation Projects for clients and within IBM.  Also in the follow on years where I worked with multiple companies as an independent consultant in a similar capacity.