From my first-hand experience, the number 1 thing that separates a junior developer and a senior developer is one word:
Questions
That was something that I definitely had to get adjust to. A senior developer will take a deep dive asking questions to architect a proper solution to the problem.
A junior developer will not ask few questions and will construct a solution based on their own experience.
My very best lesson I ever learned was watching a senior developer talk with a potential customer for hours. To make him describe every nuance of the application he wanted to be built.
Leave nothing to chance.
Ask questions…
Durr Out🎤💧