Turning pro is a mindset. If we are struggling with fear, self-sabotage, procrastination, self-doubt, etc., the problem is, we're thinking like amateurs. Amateurs don't show up. Amateurs crap out. Amateurs let adversity defeat them. The pro thinks differently. He shows up, he does his work, he keeps on truckin', no matter what.
Steven Pressfield
Work, Adversity, Thinking 