Design Apps for Fingers on iPad, iPhone, and iPod Touch
Although the Multi-Touch interface of iOS 6 is a feature of the iPad, iPhone, and iPod touch, it brings with it some limitations. First of all, fingers aren’t as precise as a mouse pointer, which makes some operations even more difficult on an iPhone or iPod touch than on an iPad (text selection, for example).
Still, due to fat fingers, user-interface elements need to be large enough and spaced far enough apart so that users’ fingers can find their way around the interface comfortably. Apple recommends that anything a user has to select or manipulate with a finger be a minimum of 44 x 44 points in size.
Because it’s so much easier to make a mistake using fingers, you also need to ensure that you implement a robust — yet unobtrusive — Undo mechanism.
You don’t want to have your users confirm every action (it makes using the app tedious), but on the other hand, you don’t want your app to let anybody mistakenly delete a page without asking, Are you sure this is what you really want to do? Lost work is worse than tedious. Fortunately, the iPad supports the same shake-to-undo feature as the iPhone.