In the manga, Tanjiro and Kanao don't end up getting married. The story focuses more on their battles and character development rather than romantic pairings.
One great tanjiro and kanao fanfiction could be where they go on a journey together to find a rare herb for an ailing comrade. In this story, their relationship deepens as they face various obstacles in the forest.
You can start by looking on fanfiction platforms like Archive of Our Own (AO3). It has a large collection of fanfictions, and you can search specifically for Tanjiro and Kanao stories. Another option is Fanfiction.net, though the interface might be a bit less user - friendly in terms of filtering. Some Tumblr blogs also share and recommend good fanfictions in this category.
The popularity of Tanjiro and Kanao lemon fanfiction may be due to the chemistry between the two characters in the original Demon Slayer series. Their relationship is full of potential, and fans like to explore the more romantic and sensual aspects of it through fanfiction.
First, study their characters well. Know Tanjiro's kind and determined nature, and Kanao's shy yet strong side. Then, think of a unique plot, like them teaming up to save a group of children from a new type of demon. Start with a strong opening that grabs the reader's attention.