Best practices
Consider a task from the perspective of the physical world to find inspiration for a nearby interaction.
Use distance, direction, and context to inform an interaction.
Consider how changes in physical distance can guide a nearby interaction.
Provide continuous feedback.
Consider using multiple feedback types to create a holistic experience.
Avoid using a nearby interaction as the only way to perform a task.
Device usage
Encourage people to hold the device in portrait orientation.
Design for the device’s directional field of view.
Help people understand how intervening objects can affect the nearby interaction experience in your app.
For the complete guidance, including worked examples and illustrations, see the canonical page: https://developer.apple.com/design/human-interface-guidelines/spatial-interactions