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Some folks interested in copyediting/proofreading, while passionate about the material they might be working on, lack the proper skills. I want to take a moment to point out that CE/PR require a very tailored style of reading that exceeds the scope of knowing how to spell.
If you're doing CE/PR for a publisher, for example, you NEED to know about style guides. This is nonnegotiable, and requires dedicated attention. Two popular guides are Chicago and AP. Find out which one you'll need for the work you want to do, and learn it inside and out.
Become an compulsive researcher. Good CE/PRs know they don't know everything and question what they DO know frequently. Google assumptions made by the author. Have M-W (or the client's preferred dictionary) open and look up preferred spellings.
If you're CEing, you need to be able to construct a style sheet in addition to marking up the manuscript. If you're PRing, you need to read a style sheet. Refer to it often as you work. The client may have a preferred format for style sheets. You need to be aware of this.
You are not just a human spellcheck. To understand what I mean by that, I recommend investing in copies of The Copyeditor's Handbook by Amy Einsohn and The Subversive Copyeditor by Carol Fisher Saller.
If you're working in Chicago, the CMS website offers a good collection of "workout" quizzes to test your knowledge and get more familiar with their guidelines: http://cmosshoptalk.com/chicago-style-workouts/
Additionally, if you're serious about honing your CE/PR skills, I strongly recommend investing in memberships to EFA and ACES. Not only do they provide community, but educational courses as well:
https://www.the-efa.org/
https://aceseditors.org/
https://www.the-efa.org/
https://aceseditors.org/
All this is to say, you MOST LIKELY cannot apply for a CE/PR position or launch your own CE/PR business WITHOUT training for it first. You might have an English degree, and maybe you even taught English, and both of those things are great! But they do not make you a copyeditor.
I see people who are passionate about spelling and grammar looking to add "copyeditor" to their resume. Just be aware that before you do, you need to put in a little research and studying first. This work is so much more than spotting typos.
