Most successful people share the same handful of things in common:
They are disciplined with their time
They know how to stay focused on one goal at a time
They have mentors and other wise people they can turn to for advice
They have mastered one (or multiple) valuable skills
Etc.
But in the software industry in particular, I have noticed that the most successful project managers have this 1 habit in common:
Relentless Curiosity
And here's why:
Projects are an evolving species. Things change constantly. It's impossible to "know" everything all the time.
The variability in project demands an unwavering ability to ask, seek, and find answers to obscure conversations, so that they root out any ambiguity in the projects they are working on.
What's that?
What does that mean?
Who needs to know about that?
The best project managers ask questions.