At its core, a book is not only the vision of its author; it is also a collection of words on a page. By necessity, the arrangement of those words should work. What "work" means specifically will depend on the genre, but all books share many commonalities.
In his book The Science-Rejection-Letters: A Step-By-Step Guide to Analyze Rejection Letters in Order to Improve Your Writing & Get Published, Salt Cay Writers Retreat faculty member Jeff Kleinman of Folio Literary Management offers this list of the key elements a story needs to grab the attention of an agent or an editor:
Unstoppable momentum. Things happen at an appropriate rate. Plot points are revealed at just the right moments. Characters move, think, and speak in accordance with their surroundings.
Empathetic characters. Are the characters worthy of a reader's care and attention? The despicable character can have some appeal, but more often than not, it's a character agents and editors and ultimately readers care about deeply that they'll want to live with for 200 or 300 pages.
Solid prose. Not every book needs to be an ode to the wonders of language, but your writing does need to be serviceable. Write in a way that is interesting and pleasurable to the eye and the ear.
Urgency. Imagine your main character reaching out to grab your arm and saying, "There's something I absolutely have to tell you! You have to stop everything and listen to me!" Are you conveying that same sense of narrative urgency, of something very important at stake for the character?
Surprise. It's never a bad idea to start your book in an unexpected place - perhaps in medias res (i.e., in the thick of the action), or just in a setting or time that the reader didn't expect.
In addition to Kleinman's advice, here's what the other Salt Cay Writers Retreat faculty members have to say about the craft of writing:
Robert Gookrick, #1 New York Times bestselling author:
"Write with audacity. Be brave."
Erin Niumata, Folio Literary Management:
"Read your dialogue out loud and tape yourself, or have someone read it back to you. Then you'll know if it sounds natural or forced."
Lorenzo Carcaterra, #1 New York Times bestselling author:
"Do your best not to end sentences in "ing" words--they are weak. Words ending in "ed" are better--stronger, sharper."
Erin Harris, Folio Literary Management:
"Don't rush through revision. Writing a good book is difficult work, and it's generally a slow, painstaking process. Enjoy the journey!"
Jill Marr, Sandra Dijkstra Literary Agency:
"Join a read and critique group. You will get valuable (and free!) feedback on your work and reading and offering critiques for others will help you grow as an author."
Next up in the "Breaking In" series, the key essential to keeping the attention of an agent or editor: Voice.
The Salt Cay Writers Retreat, held October 20-25 on a private island in the Bahamas, offers novelists, memoirists, and narrative nonfiction authors the opportunity to improve their work through small-group workshops and one-on-one meetings with faculty members in a gorgeous and inspiring setting.