Cut anything from your story that does not serve it. Any unnecessary parts will distract the audience from the important parts of your story. The best way to avoid fluff is to plan well and have a definite goal in mind before you start drafting. When editing your drafts, your goal is to get to a point where to remove any single paragraph, sentence, or word would cause the story to not make sense. Be concise both in your writing and the plot itself. Create an elegant flow from scene to scene by tightening down on every necessary detail.