Apple has updated its Human Interface Guidelines for the Apple Watch to help mobile developers better understand the foundations on which Apple Watch itself was designed and best practices for creating Apple Watch apps.
These new Human Interface Guidelines provide an overview of the functionality behind gestures, force touch, digital crown, and side button. It also covers topics on app components such as notifications, glances, WatchKit Apps, navigation, modal sheets and handoff.
The UI Elements section provides overviews of labels, images, groups, tables, buttons, switches, sliders, maps, date and timer labels, and menus. It also provide an overview of the watch specifications including screen sizes, layout, typography, color, customization, home screen icons, menu icons, and animations.
Other resources are also available including guides which contain reference information to help design the elements of an app. There are also templates which provide layout specifications to help position content in an interface.