When writing fanfiction, you should pay attention to the following things to avoid writing as Mary Sue: 1. Respect the original work: Doujinshi is written out of love and respect for the original work, so it must respect the style, character setting, and storyline of the original work. When writing Doujinshi, one must be careful not to over-tamper with the original or ignore the original setting. Otherwise, it would be easy to write it as Mary Sue. 2. Prominent original features: Doujinshi is a second creation, so it is necessary to highlight the characteristics and style of the original. When writing Doujinshi, you can borrow the elements and settings of the original work as appropriate, but you need to pay attention to maintaining your own style and personality. 3. Avoiding excessive beautification: Doujinshi is an adaptation of the original work, so it is necessary to avoid excessive beautification of the characters and plots in the original work. When writing doujinshi, you can add your own imagination and creativity as appropriate, but you need to pay attention to maintaining balance and not over-glorifying the original. 4. Grasp the degree: Doujinshi is a kind of creation, so you need to grasp the degree. When writing Doujinshi, you need to be careful not to over-modify the original or ignore the original settings. At the same time, you can use your creativity and imagination appropriately, but you must also pay attention to maintaining balance. 5. Keep it real: Doujinshi is a type of re-creation, so it needs to keep it real. When writing Doujinshi, you need to pay attention to maintaining the character's personality, behavior, and plot to be realistic with the original. You can also add your own imagination and creativity, but you must also pay attention to maintaining the authenticity of the original. Writing doujinshi required respect for the original work, emphasizing the characteristics of the original work, avoiding excessive beautification, grasping the degree of perfection, and maintaining a sense of realism. These key points helped to avoid Mary Sue and create more interesting doujinshi.