Do Judge a Book by its Cover

How many generations have grown up hearing, "Don't judge a book by its cover"?  I'm guessing as many generations as we can trace, all the way back to the first books ever published in China and Rome. And, of course, the advice isn't really about books; it's about not judging people or situations at first glance, but learning more before you make assumptions.
Books, however, do get judged by their covers, millions of times a day.  You do it, I do it; it's inevitable.  That's why so much effort is put into the art department at publishing houses.  There's a science to it, and experts know what kind of cover is going to jump off the shelf and make you want to buy it.
If you're fortunate enough to sell a book to a huge publishing house, you'll have phenomenal artists crafting a great cover for you.  If you sell to a small publisher, the artists might be wildly gifted or terribly amateurish.  Either way, you will likely have zero input in the matter.  Did you see the number I just used?  ZERO.  The art department usually isn't very interested in what a writer thinks would look good.  Pictures, fonts, graphics-- that's their field, and they don't want advice from you, any more than you want advice from them about your writing.
I know, I know-- you've been working on this book for months, maybe years, and you've spent hours and hours imagining just the right cover art.  You can picture the fog-shrouded castle, or the comic-book art of the detective's face, or the bright red high heels of the woman in a raincoat, or the sad little child staring out of the rain-drizzled window-- it's been in your head for a whole lot longer than it's been in the artist's head, who just got handed your manuscript this morning.  But it's a rare publisher that will ask you how you envision the cover.
You're simply going to have to let go.  Be grateful that you're getting published, hand it over to the cover designers, and hope they surprise you with a cover even better than you imagined.
But let's say you self publish an e-book, online.  This is now a book of a different color, and you not only have input, it's 100 per cent up to you.  Your cover could make or break sales, and unless you're as talented at cover art as you are at writing, you're in a predicament.  You can hire an artist (and many writers say it's worth every penny), or you can get your friend or your kid to whip something up for you, or you can use stock footage available for free.  You can opt out of art and just use lettering.  You can design something yourself with software on your computer.  You can take a photo and use that.  But whatever you choose, study the options and advice online, from experts in the field.  Make sure your title can be read when the cover photo is the size of a postage stamp on someone's computer screen. Make sure the font matches the genre of your book.  Lettering conveys tone, just as the art does.  Take time to make sure your cover really captures the essence of your book, and makes someone want to check it out.  Because, believe me, no matter how fabulous your book is, people are definitely going to judge it by its cover.