Explore the art and science of diagramming in this 32-minute conference talk from linux.conf.au. Learn how to create effective diagrams that convey complex information clearly and concisely, enhancing stakeholder buy-in and project understanding. Discover key principles such as cognitive bandwidth, consistency, discriminability, and Gestalt laws of proximity and similarity. Master techniques for emphasis, visual expressiveness, and color usage, including the ColorBrewer 2.0 tool. Apply these skills to improve UI design, application development, and overall communication in open-source projects and beyond.