The story of Genshin Impact is definitely worth praising. It combines elements of fantasy, adventure, and mystery, creating a unique and immersive narrative. The developers have put a lot of effort into making the story compelling and it shows.
Create an engaging plot. Don't just make it about the harem aspect. Maybe the main character is on a quest in Teyvat and along the way, they form relationships with different characters. For instance, they could be searching for a lost artifact and during this journey, the harem starts to form. Also, make sure the interactions between the characters are natural and not forced.
Good Genshin Impact fanfiction often has well - developed characters. It stays true to the personalities of the original game characters. For example, if it's about Zhongli, it would capture his wisdom and elegance. Also, an interesting plot is key. It could be an adventure in a new area of Teyvat not explored in the game, or a different take on the main story's events.