What is the single most differentiating factor that made the successful person very good at what they're doing? (quality, skills, habits, characteristic or personality)

I am currently a Project Engineer with a Mechanical Engineering degree working in the Oil and Gas industry. I am hoping to transition into becoming a Artificial Intelligence researcher. How do you think is the best way to achieve this? Do I need to spend a few more years taking another degree for it?

How do you plan your day when you play multiple roles in the company?