Information architecture (IA) is how you structure and label content. Bad IA makes users feel lost. Good IA feels invisible.
Card Sorting
Ask users to group your content categories. Open card sorts reveal mental models. Closed card sorts validate your structure.
Labeling
Use user language, not internal jargon. "Settings" beats "Configuration Management." Test labels with real users.
Depth vs Breadth
Shallow structures (many items per level) vs deep structures (many levels). Aim for 3 clicks to any content, maximum.