Strategy+Business relates the 10 principles for chanage mangement. Most important is to remember that not just processes, but people have to change. Everyone needs to be involved, needs to understand the changes, and needs to 'belong' to the process if the change is to be real and lasting:

Most leaders contemplating change know that people matter. It is all too tempting, however, to dwell on the plans and processes, which don’t talk back and don’t respond emotionally, rather than face up to the more difficult and more critical human issues. But mastering the “soft” side of change management needn’t be a mystery.

...via elearningpost