User-centered design puts the people who will use the thing at the center of the process that makes the thing. That sounds obvious. It is not how most products get built. Engineers build what is easy. Executives build what they think will sell. User-centered design builds what people actually need.

The approach emerged from human factors research in the mid-20th century. Donald Norman brought it into product design in the 1980s. The core method is iterative: research, prototype, test, refine. Talk to users before building. Show them rough versions. Watch what they do. Adjust.

Principles of user-centered design

• Understand users and their context
• Involve users throughout the design process
• Iterate based on feedback, not opinion
• Design the whole experience, not just the screen
• Test with real people on real tasks

The hardest part is listening to criticism of work you made. Nobody enjoys watching someone struggle with a prototype they spent weeks building. But that struggle is data. It points to what needs fixing. Teams that skip this step usually ship products that work for the people who built them and confuse everyone else.