Take out pen and paper, or create a new file in your word processor.
List the numbers one through ten on the left-hand side of a page, leaving space in between them to write a couple of sentences.
Next to the number one, write, “The trouble begins when” and fill in the first plot point or inciting incident of your story.
Leave number two blank.
Next to the number three, write, “Everything gets worse when” and fill in the next plot point or the first turning point.
Leave number four blank.
Next to the number five, write, “Everything gets much worse when” and fill in the next major plot point.
Leave number six blank.
Continue that way with your plot turns until you get to the book’s climax or dark moment. Next to that odd number, write, “All hope is lost when” and fill in the climax.
Now you have a list of all the major plot turns in your story.
Go back to the even numbers and write down what your characters do about the plot point written just above. You don’t have to cram it into one sentence, but you do need to get a sketchy bridge from the last plot point to the next plot point.
Go back and remove the numbers.
You now have a rough synopsis of your novel.
No it’s not perfect, and it probably won’t wow an agent or an editor, but you’ve done the really hard part – simmered that 400-page work of blood, sweat and tears into something of the proper length that you can edit into the world’s greatest synopsis.