In the book, Turning Pro, author Steven Pressfield talked about what separates amateurs from professionals and how a professional became who they are.
I will write about what these aspects mean to me personally.
The professional is courageous
The pro learns to live with his inner demons of fear and doubt by confronting them. He knows there are others who will be rooting for him, but he enters the battle alone.
The professional will not be distracted
The pro sees the work in front of him, and that is his singular focus.
The professional is ruthless with himself
The pro believes in producing work of excellence, by his own standard. If the pro’s work fell short of that standard, he terminates the bad work and re-does without a second thought.