Designing an app for mobile devices involves taking into account the specific features of the smartphone platform. Mobile app design should be focused on the following general principles:
• A goal-driven approach
• Make it simple to use
• Emphasizing the flow of actions
• Making it readable
• Keep in mind the features of the platform you are using (Android or iOS)
The last point is perhaps the most important; users expect an app to behave in a way that is easy and intuitive to them and that uses the established features of the platform it is designed for. That means an app needs to be designed according the platform-specific design rules that are already established. The design also needs to consider fonts, buttons and interface objects and the way that they are presented to the user. Once again, though there may be no specific rules, it is best to follow what’s already established and acceptable to users.