When you're writing, you need to consider the "so what" factor—that is, whatever it is that makes the reader care about your story.
Let's say you have a story about a woman in her 30s who is divorced and looking for a new romance. So what? I know a dozen women in my own neighborhood who fit that description. Why should I care about what's happening to the woman in your book?
Is it her personality? Is she funny? Quirky? Always getting into trouble?
Is it the way she finds romance? Is there a mystery involved? Suspense? Danger? Or does she continually reject the guy next door who is perfect for her?
There has to be an investing reason for the reader—and it's usually the characterization, the plot or both. The more reasons a reader has to invest in your novel, the more they're going to like it.
Take some time to evaluate your novel and your audience. Look at your plot and ask yourself, "So what?" Then look at your character and ask, "Who cares?" When you can answer those two quesionts, you're on the right track.