You’ve written a book and, proofed it, read it through more than once for problems, including once aloud. Now… about that cover.
Covers are tricky beasts. I have one friend who wants to make the cover himself. He’s – pardon the irony here – dead set on it. A talented plotter and writer, he wants to use generic Hubble photos with some tweaks. And there’s no dissuading him either. I’ve tried. But just because there’s no way to sway him, doesn’t mean there’s no way to warn others: Covers can be considered your single best piece of advertisement for your book. So it’s best to give them time, and consideration. Art is not incidental and shouldn’t be arbitrary. The cover won’t be ignored.
So, let’s get this out of the way: the content of your books are judged by the cover. Really, that’s the first hint that a reader has about who is in the book and what’s going on inside, so it’s impossible to judge them harshly here. In fact, many readers make a rainbow out of their bookshelves, it’s a whole meme, the cover’s so important (part of what I don’t like about CreateSpace is the inability to dress up the spine of a book, for example). That means, if your cover is a kid’s disproportional and unprofessional drawing, your book could easily be considered amateurish. Likewise, if you use a tonne of different fonts, glaringly bad colour choices, boxy photos from google searches (which could get you in real trouble if the image belongs to someone) … in short, if you wander into these pitfalls, including covers that have little to nothing to do with the book, and doing the design yourself, you could adversely impact your book.
So what do you do?
You pay a professional designer / artist, is what. And, though you can have discussions and make lots of suggestions… don’t argue with the artist. The amount of disagreement you do usually reduces with the amount of experience they have. Make sure you look at their work first, and then… trust them. You chose them for a reason, and you can be explicit about what you’re paying for: these folks know what they’re doing. Your final product may need a few tweaks in Photoshop or Pixlr (ahem, the latter is free), but you will have accomplished the one thing many writers take too much for granted: you will have made a great advertisement for your work!
Me? I’m an artist. I have a strong image of what I want in my head when I think of a cover. So what do I do? I realize I’m not a designer. I’m not a book-cover designer. That’s why I work with those types. These cover designers are artists in their own right, often trained in the type of technologies you just don’t want to mess with. Work with them, and don’t discount the importance of your cover. After all, what readers see is the first thing anyone will know about your book.
Make the first impression count!