Well, being prefects means they are in a position of some authority. This new role gives them opportunities to show their trust in each other. They might have to make decisions that affect the whole school, and they always consult each other first. They also defend each other from any false accusations or criticism from other students. This loyalty and mutual respect in their new roles as prefects take their friendship to a whole new level. They become even more inseparable as they face these new challenges together.
In fanfiction, their friendship often develops through shared challenges. For example, when they face a new dark magic threat in the wizarding world, they rely on each other more. Harry's leadership, Ron's humor in tough situations, and Hermione's knowledge combine to make them closer. They also develop their friendship by having deep conversations about their fears and hopes for the future. Maybe Harry shares his concerns about being the Chosen One, and Ron and Hermione support him wholeheartedly.
In many fanfictions, their friendship develops through shared adventures. For example, they might go on a quest outside of Hogwarts together, and during that time, they learn more about each other's fears and dreams, which deepens their bond.
In the fanfiction, after they become Chunin, they might be assigned on more difficult missions together. This would force them to rely on each other even more. They could have long conversations during these missions, discussing their past experiences, their families, and their dreams. Naruto might share his dream of becoming Hokage in more detail with Shikamaru, and Shikamaru could talk about his desire to make the village a better place using his intelligence. Through these shared experiences and conversations, their friendship would grow deeper.
Well, in this fanfiction, perhaps Harry and Hermione become really strict prefects. They could be known for always following the rules to the letter. This might make them a bit unpopular among some students at first. But as time goes on, they show that they are fair and only enforce the rules to keep everyone safe. Also, they might use their influence as prefects to get more resources for their studies and share them with their friends. Maybe they convince the teachers to open the library for longer hours or something like that.
Their relationship might develop with more trust. Since Harry chose Hermione for the ball, she might feel more special to him. They could start sharing more secrets and having deeper conversations about their lives, families, and their fears about Voldemort.
Their friendship could become even stronger. In the orphanage setting, they'd have to rely on each other more. They might share the responsibilities of taking care of the orphans, which would make them closer. For example, Harry could use his experience of being an orphan to comfort the children, while Hermione would use her intelligence to manage the orphanage's affairs.
Often, their friendship evolves as they learn to understand each other's weaknesses. Ron realizes that Harry has a heavy burden as the Chosen One, and Harry comes to understand Ron's need for recognition. They support each other in these aspects, which helps their friendship to develop. For instance, when Ron is feeling overshadowed by Harry's fame, Harry makes an effort to include Ron in important matters more, and Ron starts to be more confident in his own abilities because of Harry's trust in him.
In many fanfictions, Hermione's friendship with Slytherins often starts with a common goal. For example, they might be working on a complex school project together. Hermione's intelligence and determination can break through the initial Slytherin stereotypes. The Slytherins, in turn, may show Hermione a different side of Hogwarts' social structure. They could introduce her to some unique magical knowledge or skills that are more prevalent in Slytherin house. This gradually builds respect and friendship between them.
They could become even closer as they face the challenges of a new country together. Maybe they'll rely on each other more than ever.
Their relationship could develop in a romantic way. Maybe during their search for the secrets of the Deathly Hallows, they rely on each other more and more. The shared danger and the pursuit of a greater goal make them realize their deep feelings for each other.