One common element is the combat aspect. In Ranma 1/2, there are all kinds of martial arts battles, and in RWBY, there are intense battles with weapons and semblances. This makes for great fight scenes when combined in a crossover. For example, Ranma could use his martial arts skills against Grimm in RWBY.
One common theme is the clash of cultures. Since Ranma comes from a very different world than RWBY, there's often a focus on how his Japanese - influenced upbringing and martial arts background interact with the more Western - inspired RWBY world. For example, his ideas about honor and combat might be different from what the RWBY characters are used to.
To write a good Ranma 1/2 crossover fanfic, start by brainstorming unique scenarios. Think about how the different rules of the two worlds will clash or complement each other. For instance, if it's a crossover with 'One Piece', how would Ranma deal with the Grand Line's strange phenomena? Then, focus on character development. Show how the characters from both universes grow and change as a result of their interactions. Also, don't be afraid to add some humor. Ranma 1/2 is known for its comedic elements, and this can make the crossover more engaging. Finally, make sure the pacing of the story is right. Don't rush the plot or let it drag on for too long.
One great Ranma 1/2 and RWBY crossover fanfic is 'The Martial Artist in Remnant'. It has an interesting plot where Ranma's martial arts skills are put to the test in the RWBY universe. The characters from both series interact in a really engaging way.
I really liked 'Crossing Realms: Naruto, Ranma, Yuyuhakusho'. In this fanfic, the author does an amazing job of integrating the different power systems. For example, the chakra from Naruto, the cursed springs from Ranma, and the spirit energy from Yuyuhakusho. The interactions between the characters are also very interesting. Naruto is always curious about Ranma's transformation and Yusuke is constantly challenging Naruto to fight. It's a fun read for fans of all three series.
Friendship is also a big theme. Since both Ranma and Naruto value friendship highly in their original series, in the crossovers, they usually form a strong bond. They learn from each other's strengths and support each other in facing various challenges.
There's also 'Ranma and the Huntresses'. In this fanfic, Ranma finds himself in the world of RWBY and has to adapt to the whole concept of Huntsmen and Huntresses. It delves into how his martial arts skills can be useful in this new world filled with Grimm and other challenges. It's really cool to see how he forms relationships with the RWBY characters like Ruby, Weiss, Blake, and Yang.
Character interaction. When the characters from Naruto, Ranma, and Yuyuhakusho interact in a believable way, it makes the fanfic great. For instance, if Naruto tries to understand Ranma's curse and Yusuke from Yuyuhakusho is there to mediate or add his own perspective. Also, a good crossover fanfic should have a coherent plot. It can't just be a random mash - up of the three universes. It needs to have a reason for bringing these characters together, like a common threat or a quest that requires their combined skills.
A fem Ranma crossover fanfic could involve crossing over with a historical drama. Fem Ranma could be transported to a different historical period, like feudal Japan or Victorian England. In feudal Japan, she could use her martial arts to become a respected warrior or a protector of a village. In Victorian England, she might have to navigate the strict social rules while still being able to show off her fighting abilities. Another interesting crossover could be with a superhero universe. Fem Ranma could be a new superhero or an anti - hero, using her martial arts and unique situation (being male - female - changing) to fight crime and deal with other superheroes and villains.
Well, it could be about Harry and Cho finding themselves in the world of Ranma. Maybe they get involved in Ranma's cursed spring adventures. They might have to help Ranma deal with his rivals while also trying to find a way back to their own world.