For example, in the second draft of The Sound of Butterflies, I remember going over each scene and slowing it right down. Closing my eyes and imagining myself into the head of whoever had the point of view. What were they thinking about? How were they feeling about what they were thinking about? Where were they physically in the space they inhabited? What could they see from their vantage-point? What did the air feel like on their skin?
Of course I don't necessarily put all these details into the scene when I'm re-writing it, but it helps me find what is important to the story and to the characters' states of mind. It fully immerses me in the character's point of view and enables me to write a more authentic scene. The result is often a more sensual experience for the reader I think, and helps create empathy for the characters.
The first half of my first draft tends to move quite slowly as I explore the characters and their voices (and doing research, but that's another post topic altogether), getting to know them to the point that I can race with more confidence through the second half to get the story down, knowing that I'll be coming back to flesh things out at the end when I know more about where things will end up.
The second draft isn't just about expanding scenes. It's also about a structural overhaul, looking at the pacing, adding a scene here and there to develop a theme or an aspect of the story that seems rushed or contrived or just wrong somehow. At this rate my first draft will probably only be about 60,000 long, but ultimately I know that the book will need to be about 75,000 to tell the full story that I need to tell.
How do you work? I'd be curious to hear from a taker-outer.