Six Thinking Hats - Edward de Bono
Each hat is a different "direction" to think, a different type of lateral thinking. Systematically encouraging these six directions when you are searching for creative solutions brings lateral thinking to the problem. When you are working on a problem, stop periodically and switch hats, come at the problem from a different direction of thinking.
White Hat Thinking covers facts, data, figures, information, and gaps.
Red Hat Thinking includes feelings, intuitions, and emotions. No "reasons" are needed to suggest a possibility.
Black Hat Thinking is the process of discernment, judgment, weighing and evaluating, must always be logical and is critical. Black Hat thinking is used to assess why a proposal won't work.
Yellow Hat Thinking is the positive side of the Black Hat. It must be logical, but looks for benefits and value.
Green Hat Thinking is the process of creativity, alternatives, possibilities, implications, the larger picture.
Blue Hat Thinking is the overview and process control aspect of problem solving, making sure the solutions fits, will work and how to make it work.