Bring people together in a workshop in order to spark creativity and use a creative technique to help set a creative mind-set among the participants of the workshop. Many different creative techniques exist to help generate and develop new ideas. You can find these techniques in books and card sets about ideation, like the ones from Thinker Toys or IDEO.
When done in a group, a shared problem statement and rules.
A specific ideation technique.
A willingness and ability to use intermediate ideas as stepping stone for new ones, even if they do not solve the problem.
Avoiding idea killers, like early criticism.
Ideation sessions, individual or in groups are part of most design processes. Examples of common techniques are: using analogies and metaphors to find inspiration, organizing a brainstorm, or using “how-to” questions to come up with ideas.
Universal Methods of Design has several chapters on creativity techniques such as chapter 07 (Bodystorming), 08 (Brainstorm Inforgraphics). P20-22 and 56 (Mindmapping), p118-119