Creative ideas are a central part of solving engineering problems, generating interesting art, as well as developing successful products and innovations. Idea generation methods are a well-researched topic. Specifically, there is significant research that focuses on specific idea generation methods and how they perform. Further, some method classifications have been suggested to help understand the cognitive mechanisms involved in creative ideation as well as the differences between methods. Yet, the discourse is usually on which ideation method outperforms another or how to improve an ideation method rather than the elements, rules, constraints, and activities that comprise ideation methods. In this study 76 well-documented idea generation methods are reviewed and analyzed. We find all analyzed methods consist of 25 mechanisms. The mechanisms are discussed and classified into idea promoting and implementation mechanisms. We suggest that rather than focusing research only on methods, there should be a parallel track of research creating understanding on these mechanisms and their interactions to help increase our understanding of creativity methods, add practitioners understanding on how to get the best advantages out of creativity methods and lastly improve the way practical creativity is approached in education.