Sometimes a scene in a screenplay or novel just sits there, not doing what it's supposed to. It's an experience I've had more than once, and here are three things that I've found helpful.
If you cut this scene, would it affect the progression of the story? If not, it should go.
If you cut this scene, what essential elements would be missing?
Is there a different way to cover those essential elements? One option might be to incorporate them into different scenes.
CHANGE YOUR POV
Usually you're writing the scene implicitly or explicitly from the point of view of one of the characters. Take a few minutes to step into the shoes of each of the other characters in the scene. For each one, ask yourself:
- what do they want in this scene?
- how does that relate to what they want in general in the story?
- is their behavior in this scene consistent with the above two?
- what else might they do in this scene to try to get what they want? How would that change the scene?
Often changing viewpoints gives you new ideas that bring the scene alive.
INTRODUCE AN ADDITIONAL ELEMENT
What would make this scene more dramatic? Brainstorm whether you could add:
- a new emotion (justified by something that happens in the scene, of course)
- a new action (again, justified)
- another character whose presence would cause some kind of tension or conflict (make sure they have their own reason to be in the scene)
Give one or more of these a try when you feel stuck, I hope you find them helpful.