John Steinbeck agrees that writing small pieces will accrue over time.
It’s like a journey, or any other large project, if you think about it.
All you should focus on is the next step.
It was like starting to write a novel. When I face the desolate impossibility of writing five hundred pages a sick sense of failure falls on me and I know I can never do it. This happens every time. Then gradually I write one page and then another. One day’s work is all I can permit myself to contemplate and I eliminate the possibility of ever finishing.
-John Steinbeck, Travels With Charley In Search Of America