Ensure people understand the following simple set of rules of brainstorming before they start:
- Defer judgment
- Go for volume
- Stay focused/on topic
- Capture every idea
- Don’t challenge/critique
- Build on the ideas of others
- Encourage humour
The acid test: If you have no silly ideas in your list, then at least one of these rules is being broken
Track your progress to ensure the efficacy of this strategy.