Well you could use the Watch Orientation settings.
Step 1: Open the Apple Watch app on your paired iPhone
Step 2: Tap the My Watch tab
Step 3: Tap General
Step 4: Tap Watch Orientation
Step 5: Tap on the Digital Crown on Left Side or Digital Crown on Right Side selection
This setting is also important, because it flips the interface upside down so that movements of the digital crown correspond with on screen content.
Dave