1. Formatting Content
- Create a layout that fits the screen of the device.
- Users should see primary content without zooming or scrolling horizontally.
2. Touch Controls
- Use UI elements that are designed for touch gestures to make interaction with your app feel easy and natural.
3. Hit Targets
- Create controls that measure at least 44 points x 44 points so they can be accurately tapped with a finger.
4. Text Size
- Text should be at least 11 points so it’s legible at a typical viewing distance without zooming.
5. Spacing
- Don’t let text overlap. Improve legibility by increasing line height or letter spacing.
6. High Resolution
- Provide high-resolution (@2x) versions of all image assets.
- Images that are not @2x will appear blurry.
7. Distortion
- Always display images at their intended aspect ratio to avoid distortion.
8. Organization
- Create an easy-to-read layout that puts controls close to the content they modify.
9. Alignment
- Align text, images, and buttons to show users how information is related.
Source:www.apple.com
