First, decide which two (or more) universes you want to cross over. For example, if it's 'Back to the Future' and 'The Terminator', think about how the time - travel concepts in both will interact. Then, create a character - driven plot. Maybe the Terminator is sent back in time to Hill Valley to stop Marty from changing the future, but Marty has the DeLorean to outwit him.
You should start by researching the two universes thoroughly. If you're doing a 'Back to the Future' and 'Ghostbusters' crossover, learn about the rules of time travel in 'Back to the Future' and the technology and mythology of 'Ghostbusters'. After that, come up with a unique situation. For instance, the Ghostbusters could be called to Hill Valley because some time - travel - related ghosts are causing chaos, and Marty has to help them using the DeLorean.
Begin with a strong hook. In a 'Back to the Future' and 'Superman' crossover fanfiction, you could start with Superman seeing the DeLorean traveling through time and being intrigued. Then, you need to establish the relationship between the characters. Maybe Superman and Marty become friends and use their combined powers (Superman's abilities and the DeLorean's time - travel) to save both Metropolis and Hill Valley from a common threat that spans across different timelines.
You should start by establishing the setting. If it's a crossover with the Naruto universe, you need to figure out how Future Trunks gets to the Ninja world. Is it through a portal? Or some kind of magic spell gone wrong? Then, introduce the characters from both universes. Let them have initial reactions to each other, like Trunks being amazed at the ninjas' jutsu and the ninjas being in awe of his super strength.
First, decide on the main plot or idea. It could be something like a new time - travel adventure that wasn't shown in the movie. Then, think about the characters you want to focus on. Are you going to use the main characters like Marty and Doc Brown, or introduce new ones? After that, create an outline of the story, including the beginning, middle, and end. For example, start with a problem or a situation that requires time - travel to solve. In the middle, have the characters face various challenges during their time - traveling. And at the end, resolve the problem and show the consequences of their actions.
To start writing a chara crossover fanfiction, you should start with brainstorming ideas for how the characters will interact. Will they be friends or foes at first? Also, think about how the different rules and worlds of the original characters will blend or clash. For example, if you're crossing a magical character with a non - magical one, how will that work? Sketch out a rough outline of the story, including the beginning, middle, and end. You can start with a simple premise like 'What if these two characters met?' and then build on it. Consider the character arcs for each of the crossed - over characters. How will they change during the story?
Begin by brainstorming ideas. Think about what would happen if the 'legion' met a different group of characters. You can draw inspiration from other crossover fanfictions you've read or movies/TV shows you've seen. After that, develop your characters. If you're bringing in characters from different universes, give them new dynamics. They might be initially suspicious of each other but then learn to work together. And don't forget to set the scene. Describe the new world that is created by this crossover, whether it's a mix of the 'legion' world and another or a completely new place where they all end up.
To start writing 'Battletech Crossover Fanfiction', begin by choosing a crossover that has potential for great stories. Say you pick 'Battletech' and 'Full Metal Panic'. Research both universes thoroughly. Next, create a strong plot. Maybe the mechs are being used in a war on a planet similar to the one in 'Full Metal Panic'. Develop your characters well, like how a Battletech pilot would react to the situations in the other universe.
Begin by exploring the personalities of Robin and the character he is crossing over with. If it's, say, Robin and Supergirl, understand how Robin's detective skills and combat training would interact with Supergirl's superpowers. You can start with a small encounter between them, like they meet by accident and then gradually build up to a bigger adventure. Also, don't forget to add some conflict, whether it's internal (Robin struggling with his own insecurities) or external (facing a powerful enemy).
Begin by creating a character profile for Android 21 in this new crossover setting. Consider her goals and how they might change. Also, establish the rules of the new world she's in. If it's a world of magic, how will her powers interact with magic? You can start with a simple scene, like her arrival in the new world, and build from there.
One idea could be a crossover with 'Doctor Who'. The TARDIS could land in Hill Valley, and the Doctor could team up with Marty McFly. They could use the time - traveling capabilities of both the DeLorean and the TARDIS to fix some major time - related disasters across different universes.
To start writing 'Back to the Future' fan fiction, begin by deciding which aspect of the franchise you want to focus on. Are you more interested in the time - traveling mechanics, the relationships between the characters, or exploring a new time period? After that, do some research on the 1950s, 1980s, and any other time periods relevant to the story. You can also create a character outline for the main characters, including their goals, fears, and quirks. For the actual writing, start with a simple plot idea, like Marty has to go back in time to correct a mistake he made during his previous time - travel adventures. Then, start writing the story, making sure to keep the tone and style similar to the movies.
Begin by brainstorming interesting scenarios. If you're doing an 'It' crossover with a sci - fi story, think about how the otherworldly elements of 'It' like the sewers and Pennywise's powers would work in a sci - fi setting. Decide on your main characters from both universes. Then, create a rough plot outline. You could start with a character from one world stumbling into the other. It's all about being creative and having fun with it.