Start with the user, not the technology. Map their journey, understand their context, and design every screen around the moment of use.
Choose your stack deliberately. Native gives you maximum performance; cross-platform with React Native or Flutter accelerates time to market.
Performance budgets matter on mobile. Optimize images, lazy-load everything you can, and minimize JavaScript on initial load.
Test on real devices, on real networks, with real users. Emulators only catch part of the story.
Plan for the App Store review process from day one — privacy disclosures, permissions, and clear value propositions speed approvals.