I saw this quote today and fell in love with it immediately because it ties nicely into what I've always said about self-doubt and fear of failure.
"To accomplish great things, we must not only act, but also dream, not only plan, but also believe." - Anatole France
It's not enough to write, you have to dream of being a published author. You can make your plans and set goals to achieve them, but if you don't believe in yourself and your abilities as a writer, you won't have the persistence and motivation to stay the course when you meet with rejection.
I can't tell you how many writers I know who put themselves down, who question their abilites, some even after they've been published. Live in the here and now, but dream of bigger and better things. Put your plans in place and have the confidence to keep moving forward, despite rejection, despite the days when you're unsure and think your work stinks, and despite what anyone else says.
You have the power to make your dreams come true. Use it!