John Simmons spent a year as the Writer In Residence for London Underground (no, he didn't live down there...), and in an article in Creative Review, he revealed some of the lessons he learned from the experience of getting employees to express themselves via writing exercises and workshops:
1) Creativity is stimulated when you find a different place. For him, the different place was the Underground, for the employees it was a Quiet Room in which they could think and write.
2) There is security in privacy. He started each session with five minutes of writing that would never be read by anyone else.
3) The spur of competition can be positive.
4) Writers need confidence--too often teachers, family members and others knock it out of us and we have to re-discover it.
5) Constraints are liberating. The constraints of time and form helped participants break free of their inhibitions about expressing themselves.