David Smith is starting a series he is calling 'As I Learn Watchkit' (AILW). In his first post, David covers a method to project an Apple Watch screen onto an iPhone screen:
Sadly you can’t interact with the simulator via the mirrored copy, it is just a static image. However, even just having the life running app physically in front of me has been extremely helpful as I start to layout screens and try out layouts. I can now physically press my finger on the screen and see how much of the interface it takes up. I’ve already caught a handful of places where my initial design was way too ambitious for what a customer could actually use in practice.