Learn just enough to iterate a design quickly, use established styles, and put in a bit of effort on every piece. And you can dramatically increase your product quality.
Describing expected behavior in a story is a baseline. Make your stories even better by writing a story goal that describes the purpose of the feature.
Users inherently build a set of rules and expectations on how a system works. It is key to maintain consistency to prevent unnecessary "second-guessing".
Android's soft-keyboard can be a struggle to integrate, but it doesn't have to be! Learn the basics of this ubiquitous interface and see basic examples.