The author mentions getting a copy editor, but I would also advise hiring a development editor and/or getting feedback from beta readers. Quoting Stephen King (1): Show your piece to a number of people—ten, let us say. Listen carefully to what they tell you. Smile and nod a lot. Then review what was said very carefully. If your critics are all telling you the same thing about some facet of your story—a plot twist tha…
A development editor would be fantastic as well, I honestly just didn't know where to find one!