One of the most common reasons that editors reject submissions is the story's lack of conflict strong enough to sustain a story from beginning to end. So let's look conflict.
Conflict is what keeps a character from getting what he or she wants.
Too many writers mistake conflict for bickering between their characters. Or they think conflict is a misunderstanding between the characters that puts them at odds. Or that getting stuck in a monsoon is conflict enough to keep a story going.
But that's not conflict. Conflict is about struggling against something specific to get something specific. Dorothy gets sucked into a tornado and ends up in the land of Oz. She wants to get home, but a series of problems arise that keep her from being able to reach her goal of going home, and she and her gang of motley allies must figure their way through those obstacles to reach her goal. That's conflict.
But is that enough to sustain a story? Not really. Because there's something else we need to know about conflict.
Conflict is both internal and external.
For example, in the Wizard of Oz example (which I'll admit, I'm borrowing from the fabulous Debra Dixon's Goal, Motivation and Conflict example), Dorothy's desire to get back home is the external goal. But her internal goal is to find a way to be happy with her life. Her unhappiness, the trouble she always seems to get into in her life, motivates her to want to find a place she belongs. But there's a conflict--she doesn't know what will make her happy. So that's the conflict she has to work through to reach her goal.
So how do we bring our internal and external conflicts into play?
The best way to keep your characters' internal conflicts in the forefront is to fashion your external conflicts so that they play on the characters' worst fears. I had a character whose horrific childhood had given her a near phobia about children. She didn't like to be around them, didn't want to have to deal with them. So what kind of external conflict did I give her? She was called to investigate an assault and attempted kidnapping of a four-year-old girl. And then the little girl formed an instant crush on my heroine, which inspired her boss (and former foster father) to assign her to protective detail for the child, who was the only one who could identify the assailant. So her internal conflicts were top of mind immediately.
What about the hero? Well, his big internal conflict was that he'd married a woman who didn't want to be married when she got pregnant with his child--and it had ended about as you might expect. The woman who didn't want to be married and certainly didn't want to be a mother, leaving the hero to raise his daughter by himself. So the last thing he needs in his life is a woman with a kid-phobia who seems to break out in hives whenever his daughter is around. But at the same time, she's a cop who can help him protect his daughter, who seems to find the heroine irresistible. So it's a constant push pull between the attraction they feel for each other and the myriad reasons they shouldn't be together.
But it's also the threat to the child that allows the heroine to work through her fears and her past torment to move forward with her life and allow herself to love not only the child but also her father. And the hero's love for his daughter helps him find the patience to look past the heroine's protective walls to see the woman inside that his daughter so clearly adores. And the heroine's bravery and determination to protect his child helps him trust her enough to also share his heart.
To sum it up, your external conflict should constantly be putting pressure on the internal conflict. It should also be part of the means by which the characters resolve their internal conflicts and come together in the end.
And remember, in a romance, the internal conflict is extremely important. In many stories, it's the most important conflict. Don't give it short shrift.
So, here's the assignment for today. Think about the conflicts in your current WIP. What external conflict is keeping your hero/heroine from reaching their goals? What internal conflicts are complicating things? How do those internal and external conflicts apply pressure to each other?