Coding taught me that a human brain can’t possibly store all the information one needs to write in dozens of languages or on multiple operating systems. Programming teaches you the fundamentals of how to think. And for everything else, there’s Google.
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.