Do you have any professional editors that you would recommend?
The short answer is “No.” All the professional editors I know work for publishers, and I don’t think any of them do freelance work on the side.
The longer answer starts with a question: Why do you think you need an editor?
The answer to this is usually one of two things: either the writer in question thinks they need to have their book professionally edited before they even try to sell it to a publishing house, or else the writer is planning on self-publishing (these days, that usually means via e-book).
The first reason is a matter of either misinformation or supreme lack of confidence. For the first, publishing houses – whether they’re a traditional hard-copy house, an e-book publisher, a regional small press, or a micro-publisher – have their own editors and copy editors and proofreaders, and the author gets to vet any changes they ask for or corrections they make. (Nonfiction is a slightly different matter, but I’ll get to that in a minute.) No matter what the author does before the book gets to the publisher, that book is going to go through the publisher’s editors. It is not reasonable to pay for something that the publisher is going to pay for anyway.
On top of that, a freelance editor is no guarantee that your novel will sell. Publishing houses and their acquiring editors generally have their own style and their own sets of tastes and preferences, which may or may not line up with those of your freelancer. Since the acquiring editor at the publisher is going to be editing your book anyway, you might as well not spend your hypothetical advance money on something that may actually cost you the sale (if your freelance editor’s ideas of what your book needs are the opposite of what the slush reader’s opinions are).
Lack of confidence in a writer who is submitting their work to a publisher is the other common reason beginners hire freelance editors, and it’s a lot harder to deal with. If you don’t believe in your own work, it is really tempting to put it in the hands of someone else who can “fix” it … and who’s someone you can blame if it still doesn’t sell. However, having someone else fix your manuscript does not actually help much in improving your writing, which is what you need to do if you are truly as lousy as your inner demons are claiming. If it’s that bad, run it through a workshop, take a writing class, or put it aside and write another two or three manuscripts (it’s like how you get to Carnegie Hall … practice, man, practice).
The second reason – self-publishing one’s work – is a valid reason for wanting to hire an editor, but leads to the next question: What kind of editor do you actually need/want?
If you are convinced that your work is not publication-quality, but you still want to publish it without embarrassing yourself, you’re probably looking for a ghost writer. This is a professional writer who will essentially rewrite your book for you to get it up to speed. They’re usually hired by nonfiction authors who have expertise in something like investing or buying antiques but little writing skill, or by famous people who have neither the time or skill but whose name on the cover of an autobiography will sell tons of copies. Ghost writers are hardly ever hired for fiction because a) if the writer had wanted a collaborator, they’d have worked with one from the start, b) the finished book is highly unlikely to be the one the writer wanted to write, and c) ghost writers are expensive, and there is no guarantee that the book will sell a lot of copies (or sell to a regular publishing house) even after they’ve done their job.
A more likely choice is a book doctor, a freelancer who will do a thorough review of your work, with recommendations. This is still expensive and still give you no guarantee that the book will sell, but it may help you improve your writing, since you will have to do all the rewrites yourself. A good writing course or crit group can do the same thing much more cheaply (or free-except-for-your-time, in the case of a crit group). If you are self-publishing and don’t care about keeping costs down, a book doctor is not a totally unreasonable choice, though you have to be careful to check out your book-doctor-of-choice. Anyone can hang up their shingle and call themselves a book doctor.
Regardless of whether you do or don’t hire a ghostwriter or book doctor, if you are self-publishing you should seriously consider hiring a copy editor (or drafting a couple of friends with mad grammar skills to go over your final draft). Copy editors check the picky bits of the manuscript, like syntax, grammar, spelling, punctuation, correct word choice, fact-checking, style consistency, and clarity. (If you are writing alternate history, be sure to give any professional copy editor a list of specific things you made up. In one of the Kate and Cecy books, the poor copy editor spent hours trying to verify the existence of a non-existent opera that we’d assigned to a real-life composer.) Drafting friends is cheaper than hiring, but if you’re writing something with lots of technical stuff, hiring a pro may be worth it.
Finally, there are proofreaders. This is the final check for typos and glitches like the italics turning on and not turning off for three pages. Publishers have both copy editors and proofreaders, and let authors double-check their work. If you are self-publishing, try to persuade friends and family for this, too; this is a case where having lots of different eyeballs look it over is often as good or better than having one person do it, no matter how professional they are.