Apps display the same interface on both sizes of Apple Watch. Relative positioning lets items expand as needed to fill the available space. Elements of your interface are laid out top to bottom and left to right.

Avoid displaying too much information on screen at once. Users want to see the most important information instantly, so you don’t want to clutter the screen with inessential details. Users can easily access secondary information by scrolling.

Create visual groupings to help users find the information
they want.
For example, use negative space and separator lines to place related elements and information into distinct areas.

Use the full width of the screen. Design your content to go from one edge of the screen to the other. The Apple Watch bezel provides a natural visual padding around your content that eliminates the need for additional padding. In addition, minimize the padding between elements to avoid wasting valuable space.

Use a menu to replace buttons when appropriate. Menus offer a dedicated place to list actions. Removing buttons and replacing them with a menu frees up more space for your content.

Limit the number of side-by-side controls in your interface. Icons are more effective than text for side-by-side buttons. Limit side-by-side buttons with icons to no more than three. Although two buttons with short text labels may be placed side by side, it’s best to let text buttons span the full width of the screen.

Left align elements. Left-aligned text is easier to read, while vertical stacks of buttons with text labels, especially multiline labels, are often more scannable.