I've written about dialogue but what about the stage business? Action in a scene - a character moving through a space, physically interacting with other characters - serves several functions. It enlivens the narrative while grounding it in a fictional reality. And it paints a picture, allowing the reader to visualize the story. I'm a fan of interweaving stage business with dialogue, sometimes even using it to replace dialogue tags (he said/ she said). For example, consider:
I don't know, John said. It was there this morning.
I don't know. John buttered his toast. It was there this morning.
This example came from fellow Port Authority writer, Jamie, who smartly pointed out that the toast only deserves to be in the scene if it serves a greater purpose. It's not enough for the toast to highlight the speakers.
Now consider this:
Where's the cheque book? Nora asked, searching the junk drawer.
Dunno. John buttered his toast. It was there this morning.
I'd probably take it a little further, show John swiping a pat of butter off the block, describe the dry scrape of knife on toast. Nora, meanwhile, pulls out scissors and rubber bands and junk mail and pens. John dips his knife into the jam and spreads a thick glob of strawberry over the greasy toast. Nora slams the junk drawer shut, yanks another one open.
This is a lot of unnecessary detail and most of it would be cut back in revisions but do you smell what I'm cooking? The toast now tells us who is speaking, suggests something about motivation, and gives insight into character. It furthers the action. The toast provides subtext - something unsaid to read between the lines. The toast is multi-tasking.