The clients who received that email are ones I have a long-standing relationship with. I do not recommend copying my familiar, casual wording unless you know your clients really well.
But I do recommend pursuing projects that you want to copyedit or proofread.
Know What You Want
What genres would you like to work on? Do you like science fiction? Cookbooks? Nonfiction books about the Civil War? Biographies? Short stories? Poetry? Letting your clients know what you’re passionate about allows you to fill your calendar with work that you enjoy.
When I was a production editor at a publisher, I always kept in mind the strengths and interests of the freelance copyeditors and proofreaders I hired. A project that held an editor’s attention would likely be returned in better shape than a project the editor slogged through. If a copyeditor really didn’t enjoy working on high fantasy novels, which often have tons of made-up words and unusual spellings, I would hire them for, say, a nonfiction project because that editor had a knack for fact-checking. One proofreader might be great at spotting inconsistencies in illustrations or graphics, while another might be better at tracking timelines in novels.
Know What’s Available
Social media sites, including Facebook, Twitter, and Instagram, are good places to hear about what your clients have in the pipeline. If your clients are book publishers, almost all of them have social media accounts through which they promote their books, not only those coming out now but also new acquisitions. Publishers Weekly has other book and acquisition announcements. Perhaps you’ll spot something that will inspire you to make a new contact.
If you work with mainly self-publishing authors, join the professional associations most of your clients belong to. If you enjoy working on romance novels, for example, connect with authors in the Romance Writers of America. Self-publishing authors also post on Twitter and Facebook about books they’re working on, and I’ve seen editors offer their services in replies.
Know How to Ask
Before you go about requesting specific projects, develop a professional relationship with your clients. You should be able to first prove to them that you are a reliable and qualified freelancer.
When you return a copyediting or proofreading project, tell your client that you enjoyed working on, say, that historical fiction novel. This doesn’t preclude you from getting other types of projects, but they might remember and keep you in mind the next time a similar book comes around.
Don’t get disheartened if you aren’t hired for the project you requested. Sometimes your client might not think you’re the best fit, or maybe the schedule just won’t work out. Or maybe someone else beat you to it. There will always be other projects.