Another excellent resource courtesy of James Robertson at Column Two. Good mental models are especially relevant in knowledge work arenas where so much of what we do tends to be invisible. This checklist should help you improve the models you make, whether for your own use or for broader consumption.
Idiagram has published an excellent list of features that all conceptual models should share. To quote:
Broadly speaking we use the term ‘model’ to refer to any structured knowledge that accurately reflects and enables us to make sense of the world. Models exist both internally as ‘mental models’ and externally as ‘cognitive artifacts’. Cognitive artifacts can take many forms: written texts, spoken stories, graphs, diagrams, pictures, videos, spreadsheets, equations, computer-simulations, etc. While these different kinds of models vary greatly in their form and function, they all share certain desirable properties.