The Literary X-Factor

Whenever I'm not writing, I'm pondering about writing.
Don't look at me like that. Ask any writer, they'll tell you the same thing. Being a writer is a never-ending cycle of education and improvement. No matter how many degrees a writer has, they can never claim to be an "expert" writer. Aside from the sciences, writers are discovering new things every day.

Now, in my "ponderings", I've kicked around the theory that there does exist a literary X-factor. Playing off of Simon Cowell's belief that there is a certain, largely undefinable recipe for talent, I have come to the conclusion that such a factor isn't limited to wannabe pop stars. There's a writer's X-factor as well.

As any good writer should, I have read countless books in my day, spanning the spectrum of genres. Very few of those stories still stick with me today.

Let me ask you something: Have you ever read a book that you seemed to burn through from beginning to end like warm butter? On the flip side, have you ever read a book that was a struggle to finish? Where each turned page felt like more of a physical equivalent of running a marathon?
In both of those instances, you were witnessing the X-factor. Book "A" had it, book "B" didn't.
So how can you harness the coveted literary X-factor for your own books?

Let's look at what the bestselling books have in common:
1) Compelling plot
2) Compelling characters
3) Readablility

The first two are self-explanatory.  How do you know your book is "readable"?

I can answer that with a question.

Do you write like you talk? Or do you write to impress people with your knowledge or intelligence?
I don't necessarily mean using big, scary words. I mean the pompous, nose-in-the-air habit of spelling things out for your readers who are surely more ignorant than yourself.

DON'T DO THAT!

In my personal belief, if you speak to your readers as you would speak to any of your plethora of friends at your average cocktail party, you'll reap the rewards of increased readership.

But that's only a small step into the X-factor phenomenon. Perhaps you could help me with the rest. What sets James Patterson apart from James Smartypants? Aside from having a wicked awesome agent, what made the world sit up and take notice of J.K. Rowling, while ignoring the works of Ima Trying (of course, my examples are made up authors. My apologies to any Smartypants or Tryings I have offended.)

So writers and readers, you've read plenty of books. What are your thoughts? Aside from being a genre you love, what makes a book a page-turner?