First, you need to know the characters well. Watch the show multiple times to understand their personalities, motives, and relationships. Then, come up with an interesting concept. It could be a new adventure for Ladybug and Chat Noir, or a different take on how the Miraculous were created. After that, start with a simple outline of the plot, including the beginning, middle, and end.
One great example could be those that focus on the relationship between Ladybug and Chat Noir. For instance, there are fanfictions where they discover each other's identities in unique ways. Another example might be the ones that explore the backstories of the Miraculous holders in more depth. Some fanfictions also like to put the characters in different settings, like a modern - day high school AU (alternate universe).
Well, generally, you should look for the right community or site related to Miraculous Ladybug. Some popular fanfiction platforms could be a good start. Once you're there, there will likely be a section for submissions. You might have to format your fanfiction in a particular way. For example, use a standard font and proper paragraphing. Also, be aware of any copyright rules. You can't use copyrighted material without permission. And don't forget to give your fanfiction an interesting title that will catch the attention of the reviewers or other fans.
This event in the fanfic could also lead to new characters emerging. Maybe someone would try to take on Ladybug's mantle in a different way. Or new villains could rise, seeing the opportunity in the chaos. The magic of the Miraculous might be affected too. Since Ladybug was an important part of the magical balance, her death could have unforeseen consequences on the powers and the Miraculous themselves.
It could be that there were certain clues or familiar mannerisms you showed that made it obvious. Maybe a particular phrase you used or a way you reacted to a situation.
It could be portrayed as having more powerful abilities. For example, instead of just creating sentimonsters, it can also control the elements for a short time when a sentimonster is created. So if a sentimonster is made to look like a bird, it can also make the area around it windy like the bird is flying fast.
First, you need to know the characters well. For example, Chat Noir's flirty nature and Ladybug's more serious side can be great sources of comedy. You can create situations where Chat Noir's flirting backfires in a humorous way. Second, play with the superhero - civilian dynamic. Maybe Marinette accidentally reveals her Ladybug identity in a comical way. Third, use the magic elements in the show in unexpected ways, like the Miraculous causing some wacky side - effects.
First, you need to know the characters well. For Miraculous Ladybug, understand Marinette and Adrien's personalities, their powers, and their relationships. For Rapunzel, her kind - hearted nature and her long hair's significance. Then, think of a plot that can combine the two worlds. Maybe Rapunzel's magic hair could have some connection to the Miraculous powers.