The user experience experts at Nielsen Norman Group have found four user interface elements that are being used in Apple apps (and websites) that consistently cause usability issues. Don’t follow these practices:
Dots to Indicate Pages
The page control that is presented as a line of horizontal dots is commonly overlooked by users. The dots are often too subtle in the interface to clearly indicate to users that there is another view of content available. Instead, the recommendation is to consider if content is better accessed via navigation or text links.
Form Submit Button at the Top
Action buttons are often displayed in a navigation bar at the top of the page.This goes against the natural top–bottom workflow on the page; users expect the action button to be at the bottom. Display the form submit button under the form fields rather than at the top of the page.
Plus (+) Icon
In many mobile apps, the plus icon is used to represent a variety of functions. Avoid using the plus icon, as it can be interpreted in several different ways. As an alternative, use an arrow for expandable lists and text labels for buttons triggering any action associated with a list item.
The move icon does not clearly reveal what it does. When this icon appears within a row of a list, users are supposed to tap the icon and hold it while dragging the related item to its rightful place in the list. Nearly the exact same icon has come to mean something completely different; the “hamburger” icon, used to represent a navigation menu, looks incredibly similar to the move icon. Don’t use both at a site, and avoid using the unclear move icon.
For great examples and more thoughts on these, see 4 iOS Rules to Break.