First, think about the character you want to insert into the Marvel universe. It could be an original character with unique powers or just an ordinary person. Then, decide on the plot. Are you going to be part of an existing story arc like the Avengers' fight against Thanos? Or create a new adventure? Next, do some research on the Marvel universe's lore, characters, and settings to make your story more believable. For example, if your character is in New York, know the layout of the city as it's presented in the comics or movies.
Well, start by choosing your role in the Marvel world. Are you a hero, a villain, or something in between? After that, consider how your character interacts with the well - known Marvel characters. Maybe your character has a crush on Spider - Man or is a rival to Loki. Then, start writing scenes. You can begin with a simple introduction of your character, like where they live, what they do for a living if they're not a full - time superhero. And don't forget to give your character a distinct personality.
Begin with a concept. For a Marvel self - insert fanfic, you might base your character on yourself or create a completely different persona. If you're basing it on yourself, think about how your skills and traits would translate into the Marvel universe. Once you have the character, plan the story. You could follow the style of a Marvel movie, with a big action - packed opening. Or start slow and build up the tension. Also, think about the theme of your story. Is it about self - discovery? Friendship? Saving the world? These elements will help you start writing your fanfic.