Great papers take a lot of time and effort. Good usage of words and good flow. Transitions between paragraphs. A lot of emotion and vivid language. The structure of each paper is depending on the topic you are writing about. Great papers have great structure and bad papers are confusing for the reader to grasp. An A paper is not done the night before, it takes a couple of drafts and revisions. But a C paper can be done the night before and that is if you are lucky !