Writing a novel is a bit like painting the Golden Gate Bridge. I’m excited to get to the end so that I can go back and repaint the beginning. With the end in sight, you have a better idea of the kind of work you need to do. After all, no matter how much planning you do, there are some things you can only know from writing itself. You can write notes and outlines, you can think and think, but it’s the work itself that will teach you how to make your final decisions about plot and characters, which scenes to develop, and which to cut.
Some writers say that their characters escape them and take destiny into their own hands. I wouldn’t go so that far as that, but I’d say that characters can teach you. Developing a character, and a story, you’ll find that your book will tolerate certain outcomes and not others. If you do your job as a writer, your material will begin to assert itself, and begin to guide you. Potters talk about clay taking form in their hands. Sculptors talk about stone or wood telling them what it wants to become. Fiction writing is a little different, because you are often hunting for your clay at the river bank, inventing the stone and the tree, but once you’ve gathered materials in your imagination, you’ll find that those materials have their own properties, and your work goes best when you respect the color of the clay, the grain of the wood, the veins in the stone.
This is why I enjoy the middle and end time of novel writing so much. I’ve got my materials, I’ve shaped my characters, and my imagination can stop roaming far afield, settle down, and work with these.