When students in computational mathematics start their research work, they usually encounter a critical issue, i.e., how to write a good paper which is clear about the novelty, major difficulties, key ideas, and description in details. We will discuss about four keys: (1) how to highlight and justify the selling points of a paper; (2) how to explain the major difficulties and contributions of the paper; (3) how to provide a clear description for the logic framework of the paper; (4) how to efficiently find and correct the mistakes and typos of a paper.