“The best memoirs, I think, forge their own forms,” writes Annie Dillard, author of An American Childhood. “The writer of any work, and particularly of any nonfiction work, must decide two crucial points: what to put in and what to leave out.”

This is especially true when writing a memoir, not because you don’t want to hurt people’s feelings, or because you couldn’t possibly include everything from your life, but because your life has a natural structure, a backbone narrative, and once you find that narrative, anything that doesn’t belong on that structure will naturally fall away.

I helped an author write about his childhood growing up on a farm in Wisconsin in the 1940s. This was a decade of earth-shaking activities around the world, all of which affected Len’s life on the farm, but they had no place in his narrative, except as immediately experienced by his brother going to war. Len’s life was farm focused at the time, and though the farm changed and was later sold, he didn’t dwell on the changes or the future in his narrative. Rather, he dwelt on life’s lessons learned on the farm. The result was a snapshot of time as lived by a young boy in Wisconsin in the 1940s.

Another gentleman in his 90s wrote a memoir focused on his childhood adventure to see the 1933 Chicago World’s Fair. Against his father’s wishes, he and a friend hopped a train and journeyed to the World’s Fair, with $3 in their pockets. The majority of the book focused on this ten-day trip, and his eventual return, hungry and exhausted but thrilled, when his father asked him, “Do you have that out of your system now?” The remainder of the book was a reflection on how that adventure helped him to survive World War II and life’s later challenges. The World’s Fair was the backbone, and all else hung off of that story line.

Find your backbone and you’ll know what to hang on it.