By Mouse and Frog by Deborah Freedman

Mouse's quiet writing reverie is continually interrupted by the over-exuberant Frog, eager to add his own embellishments, including "elevendy-seven kinds of ice cream." He references Nursery Rhymes and numerous picture book classics such as The Stinky Cheese Man, Blueberries for Sal, and Are You My Mother. The dizzying array of Frog's suggestions becomes mind boggling. Unfortunately, the original story concept becomes lost in the chaos.
Both eventually realize that a great story embodies the best of both imagination and restraint. The creation of a story begins with a germ of an idea. During development and before the story is complete, some ideas will be discarded, and others modified.
The finished story will be an authentic creation of the author(s).
Finding Serendipity by Angelica Banks

As Tuesday explains to the Librarian:
"You see, I'm not a writer...My mother is a writer. I used her typewriter, and well, I don't know how it worked, but it did."
"Not it," said the Librarian impatiently. "You YOU! It's not typewriters that write books. It's writers... you can't get here because of a typewriter. You came because you have a story inside you wanting to get out."
Tuesday discovers that the story within her must be experienced and become real to her before she can write it.
A story that can "feel as real as sunshine on your face... taste like mint on your tongue...sound like lightning or the scream of someone you love dearly. It wouldn't be a good story if ...writers didn't totally believe in it..."

Several of the quotes reference the importance and joy of reading and writing and would be excellent to post in a library or classroom. However, I am fond of this from Through the Looking Glass by Lewis Carroll:
“Alice laughed. 'There's no use trying,' she said. 'One can't believe impossible things.'
I daresay you haven't had much practice,' said the Queen. 'When I was your age, I always did it for half-an-hour a day. Why, sometimes I've believed as many as six impossible things before breakfast. There goes the shawl again!”