The Copyeditor's Transcript
The beauty of being a copyeditor isn't in a fancy CV or being able to shout that you graduated with a 4.0 GPA or were magna-cum-whatever. Just as in writing, the copyediting proof is in the testing. If you can demonstrate in a practical way--that is, through taking tests--that you've got the goods, you may be able to firmly plant your foot in a publisher's door.
I had one class in college that covered, in part, proofreading marks. That's it. The rest was personal motivation and my decision to go into book typesetting after college instead of taking a summer job at a major newspaper.
I never took a copyediting class, but that's usually what I advise people who want to learn the skills. They're usually offered at community or other local colleges, don't cost a fortune, and don't require a huge time commitment. For instance, if you're in the New York metro area, NYU offers a certification class in book copyediting. These days you might even find some classes online, such as through Media Bistro or through a school's distance learning program. I can't confirm or deny the quality of those classes, but it's one of the many outlets to check out.
After you've aced--or at least survived--a copyediting class, you'll probably be familiar with the references I pointed out in the post below. You don't have to memorize everything, but you should know how to refer to those texts for editing purposes and maybe mark critical pages with Post-it notes. (I keep a Post-it on Chicago's 7.90, the pages on hyphenation.)
If you're looking to be a freelancer, you should keep an eye out for postings for copyeditors or proofreaders through Web sites like Publishers Lunch (see the widget in the right-hand column of this blog) or through sites like McMurry, Monster, Journalism Jobs. Several membership organizations have job leads too, such as the American Copy Editor's Society e-listings and the Editorial Freelancers Association free discussion board or subscription-based job lists.
Getting jobs as a copyeditor are a lot like getting writing jobs--most houses are always "passively looking" for good people. So if you have good phone skills and won't take offense at getting voice mail (and possibly no reply), you can make cold calls to your favorite book publishers and ask for the managing editor or head production editor to request a copyediting test. Sometimes you'll be required to take the c/e test even if all you want to do is proofread. Other times the publisher will have a separate proofreading test.
These jobs are also like writing jobs in the sense that you may not get any feedback if you fail the test. It's unfortunate but true that editors these days don't have a lot of time to nurture people into the field. As a freelancer you have to hit the ground running.
Which is exactly what I hope you'll do after reading this.