I've heard it both ways: God is in the details. The devil in the details. I would imagine that the version you identify with depends on whether or not you have attended to the details!
I am beginning to see that easy part of getting a book sold is the writing of it! For sure, getting a publisher to look at it is not the easy part! There are many how-to books written about getting your book out of the "slush pile" and into hands of an editor or publisher. I have been to many a session on this subject at writer's conferences. And still I feel I lucked into my current relationship. Sure,I kept sending my book off to publishers. I attended to that detail. And I have a little stack of rejection letters that I kept for practicing the formula I learned from one successful author: a rejection letter arrives...you open it, read it quickly for the bottom line, do a little dance in the front hallway and say, "Yes!!! A rejection letter! Now I am one letter closer to getting an acceptance letter!" Do this quickly before any hint of those enemies of progress, those pesky tears of frustration, can appear to muck up your dance. But back to the luck part. I sent my book of to dozens of publishers. I always checked to make sure I had names right. At first I sent the manuscript to one publisher at a time, because that was the way things worked in the olden days (two years ago?). But since many established rules of publishing have gone out the window ( for example, the courtesy on the part of some publishers of any reply whatsoever), I would do my research and mail to multiple publishers at once. And the result of that was that sometimes I got more than one rejection letter on the same day! Such a great opportunity for that dance!
Then one day, a small miracle happened. I got an email from a publisher. Tate Publishing emailed me saying they might be interested in Mad Mad Annabelle Jane. And now I am climbing this learning curve of awesomeness. How a published author becomes a successful author. It can be done, and done by me, I am certain. And we'll just see who is in the details after all!