After endless hours of staring at blank screens, scribbling notes, and putting words in a semblance of order, you have finally done it! You have finished your manuscript. But... now what?
When you choose to go the self-publishing route, writing that book seems to be the least of your problems. Everywhere you look, you can get tonnes of advice on what to do next, some of which seem to be at complete odds, some of which don't really seem to be advice at all, and in some cases, you might even question the validity of said advice (I know I do at times).
Before I launch into the reasons why you need an editor, let me tell you this. Due to the 'ease' of self-publishing, a lot of books out there simply aren't of good quality. People have spent money on it only to be disappointed by the quality. And fair is fair, you can only spend your money once. These days, more and more people take the indie author route, and they're doing it well. Indies are held up against the same standards as traditionally published authors, and let's be honest, if you want to make it out there, it's only fair that readers do!
But why do you need an editor?
They bring a fresh set of eyes to the table (not literally, obviously). You have been staring at that manuscript for so long, it makes sense to you; it makes sense to your brain, which is why it will skip over missing words.
Because they will find the grammar/spelling mistakes you (and your critique partner, and your betas, and others who have read it) have missed. Trust me when I tell you it happens. Is every book flawless? Not a chance, but there's a difference between a few mistakes and glaring errors that make the book unintelligible.
They will catch plotholes, even if you think you got them all (they're nasty buggers with a mind of their own, and they flee when you least expect it).
Finding an editor isn't hard, but finding one who is in line with your thoughts, your voice, and your ideas might be a little more difficult. This is why you should always ask for a sample edit. It will show you how the editor works, what their editing is like, and if it is in line with what you want and what is needed for your book. If it doesn't work out, that's fine. It might even be that an editor does not prefer to work in your genre. Don't hesitate to ask if they know someone who does. It's another process that you don't want to rush through (although I totally understand you want your book out there).
But what if I don't have the money? Some editors offer payment plans. Publishing is a pricey business and good editing doesn't come cheap. Don't hesitate to look around or ask once you get in touch with an editor. Who knows what can be arranged?
Keep in mind that editors are often booked in advance, and editing takes time, so make sure that you schedule with one well in advance of the publishing date you have in mind. In fact, I would suggest not setting a publishing date before you've found an editor (or a cover designer, but that's an entirely different discussion).
If there's one piece of advice I can give you as an editor and indie author, it's to not rush the process. In the long run, it won't do you any favours (unless perhaps you're already so well-established that you have a dedicated editor, cover designer, plan, and marketing in place that you can publish every month, but if you are them, I don't think you'd be reading this bit of advice). In every other case, shop around and ask questions.
And if all else fails, trust your instincts. If it's too good to be true...