In a word – no. And I’m not just saying that because I’m a professional editor.
It can be difficult to notice, but no one ever sees all the mistakes in their own books. This is the case whether we are talking about simple spelling mistakes, grammatical errors, or the larger mistakes people tend to make when they’re writing. Repetition is a common one. Even in writing this blog I often find, when I read back over what I’ve written, that I’ve repeated myself for no good reason. It’s easy to do, and the longer the manuscript you are working on, the greater the likelihood you’ve repeated yourself. And you won’t necessarily see it. Why? Because you are so closely associated with the work it can be difficult to see the problems. What you need is a fresh pair of eyes.
Can a friend help? Absolutely. Friends can certainly help point out different things that you might not have noticed, but they’re not going to pick up as much as someone in the industry. We know what will put publishers off. We know what you need to avoid, and we can point it out to you without worrying about offending you, as a friend might. We are paid to tell you the truth, although we try to do it nicely. But it is better that you know it before you try to find a publisher than get yourself a bad reputation by sending around a sub-standard manuscript. Take the plunge. Get a professional edit. It will help.
The problem with editing your own work is that you read what you think you wrote – which might not be what you actually wrote.
One of my earliest memories of working is my manager saying “you can never proofread your own work”, and she was right. Having a colleague read and edit a report before it was sent to the client was a natural part of the workflow (and proofreading what my manager wrote was a great learning tool for me).
That’s the big downside of self-employment: no one to proofread for me.