It may be tempting to post several book cover sketches from your designer and ask friends on Facebook to select their favorite. Don’t do it!
When it comes to selecting your book cover you should only consider the opinions of your ideal readers for the book. Just like they will never tell you your baby is ugly, your friends will also not tell you if your cover is bad. Unless your friends are the exact ideal readers you have targeted for your book, their opinion is not relevant. What’s worse, their kindness might actually be detrimental to your book sales.