The summary.
ORGANISE AROUND WHAT PEOPLE LOOK FOR
Not your internal structure. Sites organised by department fail because visitors do not know your departments.
Use the words your users use, and call the same thing the same thing everywhere.
LABELS MATTER MORE THAN LAYOUT
People navigate by reading, and a wrong label sends them somewhere else entirely.
Test by asking what people expect to find behind each label, before they click.
NAVIGATION MUST ANSWER THREE QUESTIONS
Where am I, where can I go, how do I get back.
Keep it in the same place on every page. Navigation that moves forces people to re-learn it.
RECORD WHAT PEOPLE SEARCH FOR AND WHAT RETURNS NOTHING
That second list is the most valuable design feedback available — it shows what people expect you to have and what words you are not using.
EVERY PAGE IS A FIRST IMPRESSION
People arrive wherever a link sent them, not at your homepage. Open a deep page in a fresh browser and read it as a stranger.
DESIGN THE EMPTY STATE
It is the first thing every new user sees, and the best place to teach the interface.
Distinguish empty-because-new from empty-because-filtered.
THE MOST DAMAGING FAILURE AN INTERFACE CAN INFLICT
Losing what someone had entered.
