So, what can designers do to make watches more usable? First, keep things simple overall. Then, why not put the manual on the back? Sound impossible? That is close to what Philippe Stark did when creating his "Sand" digital watch.
The rear base plate contains a legend showing the four main function button icons. Each icon includes one to four dots, and the corresponding function for each icon is listed. This reference is close to the hand (or wrist) and keeps the exterior surfaces of the watch clean.