If real estate can be boiled down to three words: location, location, location, then writing can too: tighten, tighten, tighten. With tightening, look for plot or character tension on each page (see Maass' "Writing the Breakout Novel"). Avoid unnecessary details and wordiness. Remember the rule of three--most people only remember up to three things in a list. Watch for redundancy. Ensure your dialogue moves the story forward.