Start with a strong inciting incident. For example, a magical portal opens and transports a group of ponies to the Pride Lands. This immediately creates a situation full of potential conflict and discovery.
One idea could be that the ponies from MLP find themselves in the Pride Lands. Maybe Twilight Sparkle uses her magic to help solve a problem that the lions are facing, like a drought. She could use her knowledge of spells to bring rain.
To write an engaging plot for a Naruto Noblesse crossover fanfiction, first, study the unique elements of both universes. For Naruto, there are ninjas, chakra, and the complex shinobi world. In Noblesse, there are powerful vampires and their hierarchical society. Combine these elements in an interesting way. For example, what if a Naruto character stumbles upon the Noblesse world? Maybe Naruto himself gets transported there. He could use his ninja skills in unexpected ways in the vampire - dominated world. This would create a lot of interesting scenarios and conflicts.
One way is to focus on the conflict between werewolves and vampires in the Vampire Knight universe. For example, a werewolf character could be introduced into the Vampire Knight school. This would create immediate tension as the vampires there have their own hierarchies and rules. The werewolf might be searching for a lost pack member who was captured by the vampires. You could also play with the idea of a forbidden love between a werewolf and a vampire, similar to the love triangles in Vampire Knight but with the added complication of species differences.
One way to create an engaging plot for this crossover fanfiction is to focus on the characters' reactions to the new world they find themselves in. Imagine Dean Winchester suddenly in the middle of London and being confronted by an angel and a demon who don't quite act like the ones he's used to from his own world. His confusion and initial mistrust could lead to some interesting dialogue and action scenes. Sam, on the other hand, might be more open - minded and start asking questions about the Good Omens universe. Meanwhile, Aziraphale and Crowley are trying to figure out who these strange American hunters are. This interplay between the characters from different universes can drive the plot forward.
First, you could combine the settings. For example, place Naruto in the world of Beauty and the Beast. Maybe Naruto is the one who gets cursed into a beast - like form, with his chakra being affected in a strange way. His friends in Konoha could be the ones who try to break the curse, similar to how Belle tries to understand and help the Beast in the original story. You can also include some of the Naruto elements like jutsus into the story. For instance, Naruto could use his Rasengan to protect the 'castle' (which could be a transformed place in the Naruto world) from enemies.
Perhaps there's a magical event that brings Tarzan and the Lion King world together. A mysterious force could transport Tarzan to the Lion King's world. He would be a strange sight for the Pride Lands animals. Tarzan could bond with young Simba or Nala. They could go on adventures together, exploring new parts of the Pride Lands. Tarzan might also introduce some of his jungle friends like the elephants or monkeys to the Pride Lands, creating a unique cultural exchange between the two very different ecosystems.
Well, perhaps in this fanfiction, there could be a common enemy for both Balto and the Lion King characters. Let's say an evil group of hyenas from Balto's world team up with Scar's old followers. Balto and Simba would then have to work together, combining their leadership and survival skills. Balto's experience with the wilderness and Simba's knowledge of the Pride Lands would be a great combination to defeat this new threat.
To make it engaging, the writer can focus on the contrast between the two worlds. MLP is a colorful, magical place, while Minecraft is more blocky and based on survival and creation. The ponies' magic could interact with Minecraft's mechanics in interesting ways. For example, Rainbow Dash's speed could be used to quickly travel across the Minecraft map. Also, including some humor would be great. Like when the ponies first see a creeper and think it's some kind of strange new monster from their world. They could try to befriend it in their typical MLP way, which would lead to some comical situations.
First, you need to establish a strong villain. For example, a new villain that has the power to disrupt both the Ninja Steel Rangers' world and the world they are crossing over into. Then, create a conflict that forces the rangers to seek help from the other group. Keep the action scenes exciting and use the unique abilities of each ranger and the crossover characters.
First, know both universes well. For example, understand the characters, settings, and magic systems in MLP and the other franchise you are crossing over with. Then, create an interesting plot that makes sense for both worlds. Maybe a problem that only the combined forces of both universes can solve.