When my husband and I joined a gym together, he introduced me to the box jump. In theory, it’s simple, a metal platform that you jump on with both feet at the same time. You can move to higher levels as you advance in ability. At least, that’s how it’s supposed to work. In theory, publishing is simple too. You have a great idea. You write it down on paper. You publish it, and it becomes a New York Times’ best seller. And you laugh. Of course, publishing doesn’t work that way. Mastering the box jump isn’t so easy either. In fact, it has many parallels with the writing life.…