Begin by choosing a crossover that excites you, say a zetsu crossover with the Star Wars universe. Consider Zetsu's personality and how it would mesh with the Star Wars characters. Is he more like a Sith or a Jedi in this new world? Develop a backstory for Zetsu in this universe. Maybe he was an experiment by the Sith or has a connection to the Force. Then, start writing from a point that makes sense, like Zetsu crash - landing on a strange planet in the Star Wars galaxy and having to figure out how to survive and what his purpose is there.
You should also focus on character development. If you're crossing with the Fullmetal Alchemist world, consider how Chrollo would interact with the Elric brothers. He might see their search for the Philosopher's Stone as something he can use for his own purposes. Start with a small scene that sets the tone, like Chrollo arriving in Amestris and observing the alchemic practices there, and then build the story from that initial encounter.
First, decide which universe you want to crossover with Tracer. Then, research that universe thoroughly. For example, if it's a Star Wars crossover, know the rules of the Force, the different species, and the technology. After that, create a plot that involves Tracer being thrust into this new universe. Maybe she's chasing a villain through a wormhole that leads to the Star Wars galaxy. Start with an engaging opening scene, like Tracer suddenly appearing in the middle of a lightsaber duel.
First, decide which universes or characters you want to crossover with Gogeta. Then, think about the plot. It could start with a disruption in the Dragon Ball universe that leads Gogeta to another world. For example, if it's a crossover with the One Piece universe, it could be a mysterious energy that pulls Gogeta to the Grand Line.
First, decide which universe you want to cross Ichigo over with. Then, research the rules and characteristics of that universe. For example, if it's a crossover with the Star Wars universe, learn about the Force and the different species. Next, think about how Ichigo would fit into that world. What would his role be? After that, start with an interesting hook in your story, like Ichigo suddenly appearing in a strange new place.
First, decide which universe Gowther will cross over into. Then, think about how Gowther's character traits and powers will interact with the new world. For example, if it's a crossover with 'Naruto', Gowther's power to manipulate memories might be a big deal in a world where knowledge and hidden pasts are important. Just start with a simple scene, like Gowther arriving in the new world.
Begin with a hook. If it's a Sinbad and a historical fiction crossover, like with the Vikings. Start with a battle scene where Sinbad's ship is attacked by Vikings. This will immediately draw the reader in. Then, develop the relationship between Sinbad and the Viking characters. Show how they overcome their cultural differences and start to work together towards a common goal.
First, choose the two or more universes you want to cross over. Then, research the characters, settings, and rules of those universes thoroughly. For example, if you're crossing over 'Harry Potter' and 'Star Wars', know the magic in Harry Potter and the Force in Star Wars.
First, choose the universe or character you want to crossover with Hawkeye. Then, research both Hawkeye's character traits and the other's. For example, if it's a crossover with Thor, understand Hawkeye's human, skill - based nature and Thor's godly powers. Next, come up with a basic plot. Maybe it starts with Hawkeye being transported to Asgard or Thor coming to Earth in a situation where they need to work together. Start writing simple scenes that introduce the crossover, like Hawkeye being shocked to see Thor land in front of him.
First, decide which other universe you want to cross Inuyasha with. Then, research both universes thoroughly. For example, if it's a crossover with the Bleach universe, understand the power systems, the characters, and the overall world - building of Bleach as well as Inuyasha. Next, come up with a central plot. Maybe Inuyasha and Ichigo team up to fight a new type of demon - like Hollow. Then start writing an engaging opening that introduces both the Inuyasha elements and the new universe elements.
First, decide on the two (or more) universes you want to cross over. If it's centipede and a magical realm, start by researching centipede characteristics. Then, think about how the centipede would fit into the magical world. Maybe it could be a familiar for a young wizard. Just start writing down ideas about how the centipede's physical features and behavior would interact with the new setting.