Well, one possibility could be that Naruto has some sort of visionary ability where he can see snippets of the future during his past adventures. For example, he might see the final battle against Kaguya while he's still on a mission with his team as a genin. This could change his approach to training and how he interacts with his friends, as he tries to prepare them for what's to come.
Maybe in the fanfic, Naruto sees a future where Konoha is destroyed. This makes him determined to change the future. He could start by strengthening the village's defenses, forging new alliances, and also trying to figure out the root cause of the destruction in the future he saw. He might also try to uncover any hidden threats within the village that could lead to such a catastrophe.
Maybe Naruto sees himself as Hokage, with the village prosperous and peaceful. He could see his friends by his side, all having achieved their dreams too.
One possible plot could be that Naruto from the past somehow gets a glimpse of the future of Konoha. He sees new threats emerging and starts training in ways that can counter those threats in the future. He might also try to influence the present actions of his friends and allies based on what he saw in the future.
Well, in this fanfiction, Naruto might see himself as Hokage finally achieving all his dreams. He could see his friends and family thriving in a peaceful Konoha. Maybe he'd also see new generations of ninja being trained under his guidance.
Well, it could be that James Potter sees the future and tries to prevent a great tragedy from befalling the wizarding world. Maybe he sees Voldemort rising to power earlier than expected and he has to figure out a way to stop it without changing too much of the future.
It could be about Baby Sakura having visions of different possible futures. Maybe she sees a future where she becomes a great hero and saves her world from a terrible danger. Or perhaps she sees a future with new friends and exciting adventures.
Obviously, Naruto would be the main character since it's about his past seeing the future. Sasuke would also be important as Naruto's relationship with him is central to the Naruto series. Kakashi too, as he is Naruto's teacher and mentor, and his guidance might be influenced by Naruto's new - found knowledge of the future.
Well, perhaps Naruto sees the future where his friends are in great danger. So he tries to change the course of events. He might start to make different decisions in his present to avoid the bad future he has witnessed. For example, he could try to resolve conflicts with certain characters earlier to prevent future wars.
Obviously, Naruto himself is the most affected as he has to deal with the knowledge of the future. But his friends like Sasuke, Sakura, and Kakashi would also be deeply affected. If Naruto saw a future where Sasuke was in trouble, he would do everything to change it, which would impact Sasuke's life. Sakura, being Naruto's teammate and also caring about Sasuke, would be involved in any plan Naruto made. And Kakashi, as their sensei, would be there to guide and support them through the changes Naruto tries to make based on his future vision.
One possible plot twist could be that Naruto's love for Kakashi from the past disrupts the timeline. Maybe his feelings cause him to unknowingly change events that were supposed to happen. For example, he might prevent Kakashi from making a certain decision that was crucial in the original timeline.