Two people rarely just stand face-to-face, talking. At least one of them fidgets. They look into each other's eyes, at each other's mouths. If one is waving his hands around, the other will glance at those hands occasionally.

They shift their weight from one foot to the other, put their hands in their pockets, cross their arms, and nod their heads. Include a few of these types of movements in your dialogue-heavy scenes to keep the story moving.

Don't forget bigger action. Is one woman moving around the room, picking things up and dropping them because she's so nervous? Is one man making a big production out of measuring coffee grounds into a filter so he can avoid looking into his lover's eyes as he tells him they're through?

Light is important and the way you describe the brightness or dimness of the light can help to emphasize the emotional mood of your story Is the sun brilliant, so sharp and clear that it brings tears to the character's eyes as it reflects from her lover's white shirt?

Weather. Don't forget weather. Is your protagonist tired? Should raindrops roll listlessly down the window glass to emphasize his exhaustion? Is the hero angry? Should the wind storm past the buildings, slamming trash into the paths of passing cars?

Make sure you add description like this. Again, it helps keep your story grounded in a physical environment and makes the characters and the action more rounded.