We have a saying around here and it is 'big chief tablet'. It simply implies keep things simple enough where you can use crayons and a big cheap tablet to explain it. Many times this is also true when it comes to app development.
Being developers one of our characteristics is that we tend to dig into the subterranean level of system architecture in order to reverse engineer a process. But sometimes the translation of what needs to happen in the UI design of an app interface, is more complex than it needs to be.
It's really easy to overthink a project and pour your heart into the programming only to have the end result be a complex demonstration of the simple idea as it started. When you are designing your next mobile app, that back away from the complex programming that is involved, and think of how you would present this to someone like, say – your grandmother.
There's an old rule that I'm sure you've heard of called KISS, and it's used throughout much of the world as it relates to songwriting, business models, and yes even app development. KISS simply means keep it simple stupid, or keep it stupid simple, which again refers to the big chief tablet reference above.
Another way to think about UI design, as pretend you only have one finger on each hand how would you use your app then?