My daughter came to me the other day, frustrated because she hadn't thought out a reason for the scene she was writing and it was going nowhere. We had a great conversation, and she was able to resolve the issue and get back to work after just a few minutes. I'd like to share some of the highlights of that conversation because I found it pretty eye-opening.
1. Every scene needs to have a reason. If the scene does not move the plot forward, help to create setting for future scenes, or show characterization, it's a do-nothing scene and should be deleted.
2. Every scene should present a problem or discuss an ongoing problem. We already know that the overall structure of a book is character + problem + goal + conflict + conflict + conflict + resolution = good story, so each scene should be a reflection of that. If there's no new conflict or discussion of existing conflict in that scene, it's outta there.
3. Every scene should include action, reaction, and emotional interpretation of the actions and reactions. A book without emotions is flat and boring. Pretend like you're the character being faced with that situation. How would you feel? Now give those feelings to your character and let them experience what you'd experience.
4. Every scene should act as a bridge between the previous scene and the next one to come. If you ended the previous scene with the discovery of a dead body, sure, you can leap ahead in time a little for the next scene, if you like, but you should be following up on what happened before. This gives flow to your story and keeps the book moving forward at a good pace.
As you edit your book, put each scene on trial - does it deserve a spot in your book? If you've got pages of fluff and filler that aren't moving your story forward or adding to setting and characterization, yank those puppies out of there. Your reader would probably skim them anyway ... save them some eye strain.