These aren't principles written for a pitch deck. They're baked into every interaction — the hints, the scoring, the order of operations, the copy.
The fastest path to the wrong solution is skipping research. Even 20 minutes with a real user surfaces assumptions that invalidate weeks of work.
A well-written brief isn't a constraint on creativity — it's the foundation that makes creativity defensible.
If you can't state a 10% improvement in plain numbers, you don't have a requirement. You have a preference.
Error states and empty states are often the first thing new users see. Design them with the same rigour as the happy path.
Every feature you add is a feature your user must understand. Subtraction is the hardest and most valuable design skill.
The interface is the last thing you design. First you define the outcome — what does success look like? — then the output follows.