Be realistic about your work. Self critique in an honest manner. Put it aside for days. Have another artist better than you give honest feed back. Have a non artist look at the painting as they can give some brutally honest assessments. Be willing to completely start over. We All want to produce good work, but just wanting to does not make make it a reality. We must put the hours and hours of work into our reality.
Successful people go to work to prosper, not just to work. They have a self-centered push to get something done.
They have exercised an incredible drive.
They never make excuses.
They focus on Goals daily, written each day.
Willing to fail, viewing failure as an opportunity to learn.