Duolingo's primary engagement moat isn't language lessons — it's loss aversion tied to the 'Streak' counter. Features like Streak Freeze, Double or Nothing wagers, and widget alerts on iOS home screens trigger dopamine loops that maintain daily active usage even when learners are busy. Great case study for student product managers.

Include this sentence in your initial proposal contract: 'Project includes up to 2 rounds of design revisions. Additional revision rounds or changes to approved wireframes will be billed at ₹1,500/hour.' The moment revisions have a price tag, clients suddenly become remarkably clear about what they actually want.

Don't sit in awkward silence for 5 minutes. Say: 'I am initially thinking of a brute-force approach where we check every permutation in O(N!), which is too slow. Let me think about whether we can store intermediate states or use a sliding window.' Walking the interviewer through your thought process gives them a chance to nudge you in the right direction.

Stop creating ad-hoc text sizes like 13px, 15px, 17px! Use a strict typographic scale: 12px (caption), 14px (body-sm), 16px (body-base), 20px (h3), 24px (h2), 32px (h1). Map all your colors to semantic design tokens (`text-primary`, `bg-muted`, `border-subtle`). When your developers implement it in Tailwind, development speed triples.