According to Wired UK:
Now draw your idea. Making paper models and moving things around on a table is a much simpler way to test the app than coding it up and hoping for the best. Have lots of people try out the paper prototype. Only when you’re happy with your paper design should you have it turned into code.
4. Submit, release
Now you have a working app, you’ll be wanting to submit it to the App Store. Apple says it aims to have all apps tested and, if approved, in the store within seven days. Towards the end of 2009, it was closer to a month. Don’t make any plans that depend on Apple.
As Tom points out, “I like the missing step between 3 and 4. That step only represents my entire career.”