There could be a mentor character who was a previous Hunger Games winner and is now guiding the new tributes. This character might have their own secrets and motives, and their backstory and how they interact with the tributes can make them a popular and complex character in the fanfiction.
A plot could involve a love story within the Hunger Games. Maybe a tribute falls in love with someone from another district during the training period. This love gives them extra motivation to survive and protect the other person. They could try to find ways to both survive the games, which is against the rules, adding a lot of drama.
Perhaps an older brother who volunteers to take his younger sister's place in the 50th Hunger Games. He has a strong sense of family loyalty and his journey in the Games could be about protecting the other tributes who remind him of his sister.
One idea could be to focus on a new type of arena. For example, an arena that is constantly changing between different biomes like a desert one moment and a frozen tundra the next. This would add a whole new level of challenge for the tributes.
It could be about a new set of tributes. Maybe there's a tribute from an unexpected district who has a unique skill, like being able to communicate with animals. This skill gives them an edge in the arena, leading to all kinds of new alliances and betrayals.
One idea could be to focus on a character who has been secretly trained for years in a unique combat style and uses it to their advantage in the Games. For example, a character who has mastered the art of using a slingshot with deadly accuracy, taking out opponents from afar.
There could be a boy from District 4 who is an expert fisherman. He uses his knowledge of water and fishing to survive in the arena. He might form an alliance with the girl from District 12, and together they face the challenges of the 50th Hunger Games. He is also very clever and can outwit other tributes.
I'm not sure specifically what this particular fanfiction is about as there could be countless interpretations. It might focus on the events, characters, or new storylines within the Hunger Games universe.
Use vivid descriptions. Instead of just saying 'the arena was big', describe it in detail. 'The arena stretched out as far as the eye could see, with towering trees that seemed to touch the sky and a murky swamp that oozed an unknown stench.' This will draw readers into the world you're creating.