Practice, Practice, Practice

How do you get to Carnegie Hall?
Practice, Practice, Practice.

All that practicing can be tiring, frustrating and unpleasant. How does one do it?
Even things that we love can be difficult. I enjoy writing, but it's hard. I enjoy playing music but it's not easy.

What is it that can allow us to struggle through the difficult moments to keep working on a lengthy project? What if we are beset by immediate distractions and demands on our time--such as family responsibility or the need to earn money? How do we keep working on the difficult, frustrating project whose payoff seems far down the line?

What sets the virtuoso apart from the hack? Edison said genius was 99% perspiration. There's the other one percent--that's needed, too, but practice, practice, practice.

I'm currently working on a cover letter that's on its 10th revision.

Hemingway was asked "How much rewriting do you do?"
He answered "It depends. I rewrote the ending of Farewell to Arms, the last page of it, thirty-nine times before I was satisfied." (excerpt from interview taken from The Writer's home Companion, Bolker, editor)

And none of that answers where the motivation to continue in the frustrating moment comes from.