Today I have for you a revising tip. I've been revising for... ever... and I've actually learned a few things that I realize might help others one day.
One, surprisingly, was as I was watching the deleted scenes from some of my favorite movies. Watching the scenes that got cut- the ones that were filmed, developed,(back in the day) edited and mixed for sound and then, at the very end, they still didn't make it into the final product - illustrates just how much everything really needs to contribute to the story, even after you think you've edited and polished and spit shined the polish job.
It also helps to listen to the director's commentary. They almost always say something like, "I really loved this scene, but..." or "I really hated to lose this scene, but..." or "this was beautifully shot/acted, but..." and after the but is always a "we had already established this relationship/motivation/plot point in another scene," or "this slowed down the pacing" or it otherwise simply didn't fit, no matter how good, into the final, finished piece.
Remember this as you revise. No matter how perfect and elegant and polished a scene or page or paragraph or sentence may be, if it doesn't contribute, it can go. Really. Go ahead and save it somewhere, if you must. I do this. I have files as long as some of my novels full of things I hated to see go, but in the end, they just didn't contribute enough to the narrative.
Directors only have so many minutes, and writers only have so many words. And while there is room in the world for epics and opuses and other vaguely gross sounding words that mean long and dense, not every book has to be 700 pages, and not every movie has to be 4 hours plus intermission. We already have a Thomas Pynchon and a Terrence Malik. There is always more room for the tight, clean, beautifully written work of a more manageable length.