The most important thing to keep in mind when designing a mobile app is to make sure it is both useful and intuitive. If the app is not useful, it has no practical value for user and no one has any reason to use it. If app is useful but requires a lot of time and effort, people won’t bother learning how to use it.
Good UI design addresses both of these design problems:
In order to be useful, mobile apps should be user-centric. Users install your app because they need to solve a pressing problem. Thus, the app has a sharply defined “sense of purpose.” Think about what it is your users will be trying to accomplish and focus on their key goals/remove all obstacles from their way.
You should bring clarity into your UI. To be effective using an interface you’ve designed, people must be able to recognize what it’s for and how to use it. There is simply no room for confusion.
Here are 9 UX design principles that I think are key for creating really great mobile user experiences. Read full article on uxplanet.org