Publishing professionals agree that professional editing is the number one most important thing that self-published authors don’t get. (The second most important is professional cover design.)
You may need a line edit (this is story editing, which you can also get from beta readers and an electronic editing program called Fictionary). Line editing is also called developmental or structural editing. You definitely need to hire a copyeditor and then, after your book is produced, a proofreader.
Full-service distribution companies and custom publishing services may handle editing for you. You can also find a great line editor, copyeditor, or proofreaders by recommendation from authors in author and publisher organizations you belong to. Or explore the options in this list of resources..
IN ALPHABETICAL ORDER
Bay Area Editors Forum
You don’t have to live in the San Francisco Bay Area to use the editors listed in this forum. And you may find a similar forum in your area, so do a web search if you want to hire locally.
Editorial Freelancers Association
EFA members are are editors, writers, indexers, proofreaders, researchers, desktop publishers, translators, and others who offer a broad range of skills and specialties. They provide resources for both freelancers and clients, including a chart of common rates. Their online EFA member directory offers authors and publishers free and instant access to the diverse assortment of highly skilled publishing professionals who make up EFA membership. The free EFA job listing service offers authors and publishers another way to find the right freelancer for the job.
FirstEditing is all about editing and only editing. Director JoEllen Taylor can assign you a line editor, copyeditor, or proofreader based on the genre of your book. Their large staff of editors worldwide can handle fiction nonfiction, and academic editing. They also offer a free editing sample to make sure you’re matched well. I like FirstEditing a lot and invited Director JoEllen Taylor to co-teach the editing portion of the Publishing Freedom Course. Find out about the different types of editing and get an instant price quote based on word count and document type. Pricing is affordable and the service is fast. You’ll get a recommendation for an editor within 24 hours.