Glances
We have the option of adding a Glance scene to a watch app, and while many will not need it, our app is going to make use of this opportunity to provide a small snippet of the information provided by the main app. The Apple Watch's Glance is reachable at all times with a swipe upwards from the watch face, and is intended as a brief, non-interactive engagement with your app. Given how easy it is to reach, the Glance enables your app to provide a limited amount of data which is immediately accessible.
You cannot add most UI objects to a Glance scene, there will be no tapping buttons and selecting from tables and the like. If your user wishes to engage more deeply with your app, she can do so by tapping the Glance screen which will open your main app, just as if she had launched it from the home screen.
When designing and implementing the Glance screen, the main challenge is not so much deciding how to code it, which is likely to be a simplified version of some part of the main app, but...