Writer’s Digest Tip of the Day - “First Aid for Scenes” from Writers Online Workshops:
…when writing a scene, first you must concentrate only on the elements that make that scene work on its own as an isolated mini-story. But eventually you must judge each individual scene’s effectiveness according to how much it contributes to the work as a whole.
Can’t decide whether or not the scene you’ve just written belongs in your story? A scene should do two or more of these four things:
1) advance the plot
2) develop the character(s)
3) illustrate the theme
4) contribute to suspense (which in turn advances the plot).