One possibility is that he would try to change the relationships around him. He might reach out to Sasuke earlier and prevent him from leaving the village. Also, he could be more strategic in dealing with the Akatsuki, since he'd know their plans in advance.
He might use his future knowledge to avoid some mistakes. For example, he could be more cautious with Orochimaru during the Chunin Exams. He might also try to train harder from the start to become even stronger faster.
Naruto's character would likely become more mature. Since he has the memories of his future self, he would understand the consequences of his actions better. He would not be as impulsive when dealing with situations like fighting with Sasuke or facing the Akatsuki. Also, he would probably be more strategic in his approach to training and battles. Instead of just jumping into things head - first, he would plan and think ahead, making him a more well - rounded and respected ninja among his peers at a much earlier stage.
He'd be more confident. In his original Genin days, he was a bit of an underdog, but with his future memories, he'd know his potential. So he'd act more boldly.
One possibility is that she would have to readjust to the basic training and teamwork. She might find it both frustrating and nostalgic. Since she has more experience now, she could use her advanced knowledge to shine in the genin tasks, like acing the survival exercises. Also, her relationships with her old teammates, like Sasuke and Sakura, would take on a new dynamic as she tries to balance her new perspective with the naivete of being a genin again.
In such a fanfic, Naruto and Hinata getting sent back in time could lead to some really interesting relationship developments. They could start their relationship much earlier, and since they already know each other well from the future, they might have a deeper connection right from the start. Also, they could use their knowledge of future events to gain allies more easily.
In a fanfic where Naruto is sent to Haven, he might find himself in a very different environment compared to Konoha. He could encounter new types of magic or powers that are unique to Haven. Naruto's strong will and determination would likely lead him to adapt quickly and try to find a way to use his skills to help the people there. Maybe he would form new alliances and friendships with the inhabitants of Haven.
Well, in this type of fanfiction, Naruto could change the relationships he had at the academy. He may befriend Sasuke earlier and in a different way, perhaps preventing Sasuke from being so cold towards him initially. Also, he could have more time to train with his classmates and help them improve too, which would make for a very different dynamic in the group.
In a 'the village want naruto back fanfic', there could be a lot of emotional turmoil. The villagers who once shunned Naruto could now be having a change of heart. Some of Naruto's old friends might be the driving force behind the village's decision to bring him back. They could go to great lengths to find Naruto and convince him that the village has changed and that he is needed and wanted there.
Her training would likely be different as she already has a lot of experience. She might focus more on perfecting basic techniques rather than learning them for the first time. For example, she could spend more time on improving her chakra control in basic jutsu like the Clone Jutsu.
He might be shocked by the advanced technology. There could be new forms of ninjutsu or combat styles. He would also have to adapt to a different social structure.