Here's another post about all the things that go into getting a book ready for publication, things that must be done many, many months in advance.
What do you look for in a book? Does a cover influence you? Here's an excellent post about book covers and some of the factors that go into their design. For my forthcoming novel of medical suspense, Code Blue, it took five passes with the design team before my editor and publisher were happy with the result. I think they did a good job. Hope you agree.