The key to creating an effective brainstorming session is freedom.
Freedom to create without judgment.
Freedom to create without friction.
The freedom to create without judgment is based on culture and trust. Who is involved in the session, and what the interpersonal connections are is important.
The freedom to create without friction is based on the process. The more processes that can be put in place that remove activities other than brainstorming the more focus is on the brainstorming.
One process is to do the brainstorming in two stages, one to get all the ideas down, the second to sort and organize so you remember in the future.
Sometimes scribes are good at reducing friction because the brainstorming participants do not have to worry about recording the ideas that come up. If it is a really good brainstorming atmosphere the scribes can cause friction because they cannot keep up.
In a really good brainstorming session, it is better that each individual take their own notes to keep the process going. They only need to take enough of a note to remember the idea during the second part of the process where ideas are expanded on.
Technology, where there is speech to text, can add to the toolset for brainstorming.
The key to setting up a good brainstorming session is creating an atmosphere where there is the least amount of friction for capturing the ideas as they come up.