He could use magic to create floating shelves for his books and potions. That would be really cool and also save space in the dorm room.
If Harry is being true to his modest nature, he might not go overboard with the customization. He could focus on making it more comfortable and practical, like adding a warm and cozy rug or some soft cushions for when he's reading.
There was a situation where a gay student in a dorm room was a bit nervous about being himself. His roommate, who was straight, noticed his unease. Instead of being judgmental, the roommate made an effort to create a safe and inclusive environment. They ended up having great conversations about acceptance and diversity, and the gay student felt more comfortable expressing his identity in the dorm room. It shows that understanding can exist even in unexpected places.
A plot could be that Harry and Hermione are looking for a way to bring back some of the lost memories of the students who were affected by a powerful forgetfulness charm during a battle. In the Room of Requirement, they find a magical device that can restore memories, but they have to go on a quest within the room to find the power source to activate it. Another idea is that they use the room to train for a magical tournament that's different from the Triwizard Tournament. They face all kinds of magical challenges created by the room itself, and in the process, they grow closer as friends and develop their magical skills even further.
A possible plot for a Harry Potter shower room fanfiction could be that the shower room is haunted by the ghost of a former student who was wronged in that very place. Harry, being the brave one, decides to communicate with the ghost and find out what happened to help it move on. Another idea is that the shower room's water has some special magical properties that start affecting the students' magical abilities in unexpected ways. For example, it makes Neville suddenly able to perform advanced herbology - related spells. And a third idea is that the Marauders once hid a prank - related map in the shower room that Harry discovers, and it leads him on a wild adventure around Hogwarts.
One idea could be a story about the Gryffindor Quidditch team in the locker room before a big match. Maybe there's some friendly banter among the players, like Harry Potter trying to boost the team's morale with a humorous speech. Another could be a story of a new student accidentally stumbling into the Slytherin locker room and the reactions of the Slytherin students.
There could be a story where a sexy mom comes to the dorm room to surprise her son with his favorite home - cooked meal. She ends up chatting with his roommates and sharing some funny family anecdotes.
Well, you could have a fanfiction where a new character creates a chat room specifically for Supernatural characters to interact with each other outside of their usual battles. It could be a place where they share their fears and hopes. Maybe Castiel accidentally enters this chat room not knowing what it is and has some really funny exchanges with the other characters. Also, the chat room could be a time - traveling one where characters from different eras of the Supernatural universe can communicate.
One idea could be a love story between a doctor and a nurse in the emergency room. They face the daily chaos and life - and - death situations together, which gradually brings them closer.
One idea could be to explore the backstories of the characters in more detail. Maybe focus on their childhoods and how those experiences shaped them into who they are in the original work. Another idea is to create an alternate universe where the rules or settings are different. For example, if it's a fantasy setting, change the magic system or the power dynamics between different groups.
Once, a group of dorm mates decided to have a blindfolded taste - test. They got all kinds of strange and random foods from the cafeteria and took turns blindfolding each other and trying to guess what they were eating. There were some really gross - out moments when someone would think they were eating chocolate pudding but it was actually liver mush. It was hilarious to see everyone's reactions.