First principles include knowing that you communicate with the user through interface, being intentional, having an overall vision, being consistent[0].
People’s expectations as to exact UI layout and behavior can vary a lot, depending on their background and previous experience (for example, on macOS I personally often look for things & shortcuts in menu bar first instead of scouting app’s interface). However, people are not stupid, they learn.
[0] Including consistency in evolution across product lifetime.