Editors sometimes focus on selling services (“I copyedit fiction, particularly genre fiction like romance and mystery”) and there’s nothing wrong with that if your clients know what you mean. For example, if you’re pitching book publishers or packagers, they don’t need to be told that copyediting includes making sure a manuscript adheres to house style.
But some clients don’t necessarily realize that the service they need is copyediting. They know that they have a problem – “I’m not great with grammar and punctuation” – but it’s very likely that all they know beyond that is that “editors” fix grammar and punctuation. They don’t necessarily know that they need a copyeditor. They may think they need a proofreader. So you have to show them what copyediting means – how copyediting solves their problem.
In other words, most potential clients have a problem. You need to be the solution. In order to be the solution, you have to put yourself in the client’s shoes: what are they identifying as the problem? If you know the problem is “I need to find a copy editor” then feel free to position yourself as a copy editor. But if the problem is “I need someone to help me get my book ready for publication” then you need to show that you provide a solution for that: “I can help you get your book ready for publication.”
The corollary is that if potential clients don’t think they have a problem, then you’re not a solution. Some people try to convince potential clients that they do have a problem (“Readers hate to read books riddled with errors!”) but I find this too quixotic for my tastes – why spend time trying to convince people that they need my services when I could spend that time connecting with people who already know they need my services?
I prefer engaging with potential clients who already know they have a problem (a book they want to get ready for publication). Then all I have to do is show them how I’m the solution.