How can I start writing an MLP and Little Mermaid fanfic?

First, you need to decide on the basic premise of your story. Are you doing a crossover, a re - imagining, or something else? For example, if it's a crossover, think about how the two worlds will interact. Then, create your main characters. Will it be mainly the MLP characters, the Little Mermaid characters, or a mix? Once you have that, start with a simple scene that sets the stage. For instance, if it's a story where a mermaid ends up in Equestria, start with the mermaid's arrival and her first impressions of this strange new land.

To start writing such a fanfic, you should research both universes. Know the lore, the characters, and the settings of MLP and the Little Mermaid well. This will help you create a more believable and engaging story. After that, think about the theme you want to convey. Is it about friendship, like in MLP? Or about following your dreams, like in the Little Mermaid? Then, start creating your characters' personalities and relationships. You can start with a simple outline of the story, including the beginning, middle, and end, and then gradually fill in the details as you write.