Assemble a group of not more than 20 people who see your problem from different perspectives.
Appoint a facilitator and several helpers. It's the facilitator's job to set the rules and keep the ideas flowing.
The facilitator starts with an explanation of the brainstorming rules before writing up the problem statement and encouraging people to generate ideas in response.
Participants write down their ideas (Scribble) on sticky notes before shouting them out (Say) and sticking them up (Slap).
The helpers are there to take completed sticky notes from participants and stick them on a wall.
After brainstorming a smaller group can cluster the ideas for voting (see Cluster and Vote).
Resources
A facilitator and helpers, marker pens, sticky notes (lots of them), flipcharts, a whiteboard or a large sheet of paper.
Refreshments and chocolate biscuits (optional)