One of the first mistakes a lot of new writers make is thinking that a book has to be written from the beginning to the end. It certainly needs to read well that way when you finish it, but that’s not always the best way to write it. I work with words similar to the way I paint: I block in broad sections with ideas and then begin developing the details.
I don’t always start writing my books at the beginning because sometimes you don’t know how something should start until you know exactly how it’s going to end. I always start with a concept. That concept is the center of the book and I work from there. That doesn’t mean that there isn’t a chronological order to the plot: it simply means that I work outside of it when I’m structuring the story.
John Irving always writes the last sentence first. Those finals words are like a beacon that he steers toward with his writing. This is a great way to work because the final words can leave a lasting impression and if you write towards them effectively, then you can maximize the impression on the reader when they walk away from the book.
You live your life one day at a time and your book has to be written one day at a time, but you don’t have to write it in that order. Stepping outside of chronology may give you more perspective and strengthen your writing.