I love romances—I write them and read them—and so I tend to be picky about how romance develops between characters.
I got two tips from a workshop given by Jennifer Crusie:
Trigger pleasant childhood sensory memories.
Early in childhood, we develop sensory memories tied to pleasant events. The cottony smell of Mama’s sewing room, or the buzzing sound of Dad running the saw in his workshop. Happy times linked to smell, sound, touch, taste, or specific visual cues.
When two people start to fall in love, one person will trigger one of those pleasant sensory memories in the other.
For example, Jenny Crusie gave a scene from her book where the heroine fried eggs in butter for the hero for breakfast. The smell of the butter brought back happy memories of the hero’s mother cooking for him.
Another example was when the heroine first glimpses the hero, and he reminds her of the one person she trusts in the world, an old mobster named Joey—the visual cue triggered pleasant memories for her because she loves Joey.
In your romance, think about how you can start to develop the romance by triggering sensory memories.
The hero and heroine start to mirror each other’s actions.
Jenny Crusie mentioned this was something a college anthropology or sociology class discovered. In a bar, couples who were successful in “hooking up” started to mirror each other’s actions. If she leaned on the bar, he did too. If he crossed his legs, she did too.
Have your characters start to mirror each other in subtle ways to indicate the advancement of their relationship. It doesn’t have to be obvious and in the reader’s face, but little things will help the reader start to track the progression of the romance.