The user interface (UI) is a critical part of any software product. When it’s done well, users don’t even notice it. When it’s done poorly, users can’t get past it to efficiently use a product. To increase the chances of success when creating user interfaces, most designers follow interface design principles. Interface design principles represent high-level concepts that are used to guide software design. In this article, I’ll share a few fundamental principles. These are based on Jakob Nielsen’s 10 Usability Heuristics for UI Design, Ben Shneiderman’s The Eight Golden Rules of Interface Design, and Bruce Tognazzini’s Principles of Interaction Design. Most of the principles are applicable to any interactive systems — traditional GUI environments (such as desktop and mobile apps, websites) and non-GUI interfaces (such as voice-based interaction systems).