Test Driven Design
It was Christmas 2010 when we deployed apparat.io a service that allowed you to package an app made with HTML, JS, CSS as a native app. For iPhone and Android you just had to upload the sources and out came a working native app, that was ready to be published to the app stores. We learned a lot about how to build apps, the signing process, the entire chain from developing an app all the way to shipping it. It was a rocky road! We had been a bit too early :).
PS: Funny enough, the service that is on apparat.io now offers exactly the same service we build years ago.