– Make things obvious. buttons should be self-explanatory and typography should be big and readable at comfortable idstance.
– Make text readable. Minimum size is 11pt, optimal size for reading is around 16pt.
– Use obvious icons.
– Descriptive Screens
– Meaning in colors.
iOS uses vibrant colors to bring out the buttons. These colors tend to work well against a white background as much as a black background. Keep in mind that colors should be used sparsely, for call-to-actions and minimal branding areas like the navigation bar. Roughly, only 10-20% of your design should have colors, or they will compete too much against the content.
The keyboard is used to input information in text fields such as search, chat or login. It’s highly customizable, for URL, Email, Phone numbers and even Emoji. You can choose between the Light and Dark themes, as well as how the action button is named (return being the default).
A high level and essential read by Apple, even if it’s just scanning the whole thing. iBooks format is also available.