I read books, I write about books, I would probably marry a book if I could find one who liked me enough. Three words to describe me mature, irresponsible, contradictory, unreliable...oh...that's four...
Great article from Flavorwire on book covers which 'ahem' coincidently look the same.
There are such strong trends with book covers.
Romance novels now must feature a male torso, unclad. Having a head on your half naked man is obviously *so* last year.
YA romance generally has a girl on the cover, usually long haired, quite often looking over one shoulder (dystopian background optional).
Thrillers often have nothing on the cover but the title, in large block capitals. No real actual humans - that would be too emotional.