Don’t get me wrong: design patterns and best practices are still your friends. Keep in mind though that apps and users are different: one solution might work for well in an app and fail in yours. It’s not a one-size-fits-all thing. Plus, you never know why an app was designed in a certain way.
Do your own thinking. Do your own design. Do your own research.
And watch out for those design guidelines, because they may not be the guidelines you’re looking for.