Editorial Services

Please note: I offer free submission packages for Black writers and discounts for marginalized writers. See below, under “discounts,” for more information!

I offer freelance editing for YA and MG fiction (no short stories, graphic novels, nonfiction, or age categories other than young adult and middle grade, please). I pride myself on my attention to detail and structure alike, as well as my accessibility and friendliness. I will push you to make your materials the best they can be without encroaching on your vision.

Here’s some information about me:

  • I’m the assistant to the president of the Jennifer De Chiara Literary Agency.
  • I’ve been in publishing since 2015, interning at Writers House, Entangled Publishing, Stonesong, and another literary agency.
  • I’m a volunteer with Beth Phelan’s #DVPit, where I offer free pitch critiques for entrants.
  • Over the course of my career, I’ve had the pleasure of working with multiple New York Times and USA Today bestselling authors, as well as major award winners and nominees (e.g. Morris Awards, National Book Awards, Coretta Scott King Book Awards, Boston Globe-Horn Book Awards, and E.B. White Read-Aloud Awards) .
  • I’ve worked with editors at Big Five publishers on their authors’ developmental editing and line editing on a freelance basis.
  • I’ve edited for authors who have gone on to sign with agents and sell their manuscripts to publishers. Here are some of the kind things clients have had to say about my work.
  • I’m happy to work directly with a writer or with their agent or editor.

My editing style is hands-on, and I’m always thinking from two perspectives: an editor’s and a writer’s. As a writer myself, I know how frustrating vague, seemingly arbitrary feedback can be. That’s why I’ll never say, for example, “cut this scene”—instead, I’ll explain exactly why this scene isn’t carrying its weight, how that affects the manuscript, and why it would be better if this scene were removed. I’m also always happy to answer any and all of your questions and help you brainstorm plans of attack for no extra cost. When you hire me, you don’t get a distant, uninvolved editor; you get a publishing professional on your team, ready, willing, and excited to help however he can.

My services, discounts, and contact form are below. Please do get in touch at markobrienbooks AT gmail DOT com if you have any questions. I can’t wait to work with you!


Query edit: $20 (one round; any additional rounds are $10)

I wrote dozens of query letters before signing with my agent, and I’ve read, discussed, and made decisions regarding countless others throughout my internships. I know what works and what doesn’t. When you book me for a query edit, I’ll look at everything from structure and format to diction and punctuation. I offer a thorough critique pointing out areas that need improvement and writing long strings of exclamation points when I love something. Most of all, though, I make sure every word counts—and shines.

Submission package: $40 (one round; any additional rounds are $20)

Most agents want sample pages included with your query, and it’s vital that these opening pages draw them in. When you book me for a submission package, I’ll help you ensure the first ten pages of your manuscript—formatted in Times New Roman, size 12, with one-inch page margins all around—and your query letter are the best they can be.

Editorial letter: $0.004/word ($40 per 10,000 words)

Drawing upon my nearly three years of experience writing these for agents and editors, I’ll review your full manuscript and write an editorial letter (two pages minimum, usually more) when you book me for this service. If you’re only concerned about big-picture elements like pacing, character, and plot, this is the option for you! My edit letter will break down what works in your manuscript and how to make it even better, in addition to what needs fixing. I always offer suggestions, too!

Full manuscript line edit: $0.007/word ($70 per 10,000 words)

I don’t like to brag, but I will: many of my clients and bosses alike have praised me for my attention to detail in particular. When you book me for a full manuscript line edit, I’ll review your entire manuscript, leaving suggestions, questions, and hearts in track changes. After noting every problem area I find on a line-level scale and suggesting how to fix them, I’ll ensure you walk away happy with your manuscript.

Full manuscript developmental and line edit: $0.009/word ($90 per 10,000 words)

Selecting this option gives you the same experience as booking me for an editorial letter and a line edit, all for a discounted price—and I’ll throw in two rounds of edits on your query for no extra charge! When you book me for this service, I’ll review your full manuscript with an eye for the big-picture problem areas, which I’ll compile in a comprehensive edit letter. I’ll leave inline notes in track changes concerning nitty-gritty details, too.


I offer free submission package edits for Black writers, and yes, this absolutely includes biracial and multiracial Black writers. There are no strings attached to this offer, and it does not expire. I may have to stagger these on my schedule a bit, so if you’re interested in taking me up on this, please get in touch as soon as you can!

I also offer 20% off the total cost of any editorial service for marginalized writers, using the definition of diversity found on We Need Diverse Books‘s website. This includes but is not limited to queer (including asexual, aromantic, trans, and non-binary, of course) writers, Native writers, writers of color, disabled writers, and writers who belong to ethnic, cultural, and religious minorities. I go by the honor system on this; you’re free to disclose your marginalization(s) to me if you wish, but I don’t require it.


Please submit your information through the form below, or email me at markobrienbooks AT gmail DOT com.

Please be sure to include your manuscript’s word count, a quick summary (this can be informal), and whether any discounts are applicable to you. Again, you don’t need to disclose any specific marginalizations—you could simply say, for example, “I’d like to take advantage of the 20% discount for marginalized writers.”

*Note: I cannot guarantee you will sign with an agent or be offered a contract with a publishing house after working with me.