An effective brainstorm lasts 2-4 hours. Start with a warm-up (15 min, energy) and the problem statement (10 min, clarity). After that come idea generation (30 min, no criticism), clustering (20 min, themes) and refinement (30 min, top 3). Provide facilitation, visual support and energy management. Split groups of more than 20 people into subgroups. Post-its, whiteboards and music help. Live Impact facilitates or coaches sessions for maximum output.