Apple's HIG emphasizes creating a seamless and intuitive user experience. Here are some pointers:
Interactive Elements: Ensure that interactive elements like buttons and links are easily tappable and visible. Use a minimum touch target size of 44x44 points. Feedback: Provide immediate feedback for interactions. For example, change the button color when it is tapped to indicate that the action has been registered. Accessibility: Make your emails accessible by using alt text for images and ensuring that all interactive elements are navigable via screen readers.