Why you should use exactly the number of words you need to tell the story

Many years ago, someone read a 50,000 word manuscript of mine and said, “It’s great, but it’s not a novel, and you’ll never sell it to New York until you add 40,000 words.”

That ingrained the idea in my head that if I wanted to sell my work to a publisher, it had to be 90,000 words, give or take — that there was no way something in the 50,000 or 60,000 word range would ever sell.

Of course, in the years that followed, several of my friends sold what were essentially novellas to New York, and I...