A few things I’ve learned in my 8 months so far of building a startup for iPhone:
1. Iteration cycles take forever.
1.5. HockeyApp and TestFlight will not replace the quick iteration cycles many are used to on the web. You’ll never be able to reliably test how new users react to new pushes.
2. Every app is a theatrical performance. Users are wowed by a well polished, usable, creatively designed app.
3. Users still like familiar though. BALANCE.
4. Talking to users is huge.