In the book, The War of Art, 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 patient
Given the pro is committed to the long haul, he understands the expectation of overnight success is not realistic. Experiencing the constant emotional roller-coaster can be exhausting, the pro fortifies his own mindset and keeps things in proper perspective at all time.
The professional seeks order
The pro sets himself up for success by organizing a productive work environment. In the work environment, the pro can minimize the noises (physical or mental) and focus on his mission.
The professional demystifies
The pro sees that the technique of his craft is the only area that he totally controls. He seeks to maximize his effort in figuring out the how-to. There are other aspects of his craft that he cannot control fully. For those aspects, he works with them but does not lose sleep over what he cannot influence.