Use UI elements that are designed for touch gestures to make interaction with your app feel easy and natural.
Text should be at least 11 points so it's legible at a typical viewing distance without zooming.
Make sure there is ample contrast between the font color and the background so text is legible.
Don't let text overlap. Improve legibility by increasing line height or letter spacing.
Always display images at their intended aspect ratio to avoid distortion.
Create an easy-to-read layout that puts controls close to the content they modify.
Align text, images, and buttons to show users how information is related.