Naruto could teach Hinata how to use the Rasengan. Since it's one of his signature moves, he could break it down and help Hinata understand the chakra control required. He might also train her in combat situations where she has to think on her feet, like he does in his battles.
If Naruto were Hinata's master in fanfiction, he could give her training in confidence - building. We know Hinata is shy, and Naruto could push her to be more assertive. In terms of ninja skills, he could teach her his unique chakra - enhanced speed and strength techniques. He could also train her in stealth by sharing his own experiences of sneaking around during his prank - playing days.
He could give her training in summoning jutsu. Naruto has experience with summoning toads. He could guide Kurenai on how to form the necessary hand seals and how to connect with the summoned creatures on a deeper level. This kind of training would not only give her a new offensive or defensive ability but also improve her overall chakra management during the summoning process.
Naruto could teach Anko his signature Rasengan. He would start with the basic steps, like how to control the chakra properly. And then move on to more advanced forms of the Rasengan.
One possibility is that Hinata would be overjoyed. She has loved Naruto for a long time, so his confession would likely make her very happy. She might blush and stammer out a response. Maybe they would share a tender moment and start a relationship right away, with Naruto finally realizing how much Hinata means to him.
In the fanfiction of their training trip, there are several possibilities. Naruto, being the energetic one, would probably push Hinata out of her comfort zone. They could meet some strange characters who give them unique training methods. For example, they might find an old hermit who teaches them a special type of chakra control. This would not only enhance their skills but also bring them closer as they face challenges together. Their bond would likely grow stronger as they rely on each other during this trip.
During the training trip, they might face some tough opponents. This would force them to rely on each other and grow closer as a result. They could also discover new places with unique chakra sources that enhance their abilities.
In a Naruto Hinata training fanfiction, the author could explore Hinata's inner strength. Maybe she's training to overcome her shyness as well as improve her combat skills. Naruto, being the supportive friend, helps her break out of her shell. This could lead to some really interesting character development for both of them, and perhaps even a budding romance in the future.
In this type of fanfiction, the training could be a way for Hinata to prove herself worthy of being on Naruto's team for a special mission. She could be training day and night, with Naruto as her occasional sparring partner. As they train, they start to understand each other's motives and dreams better. This could be a really heart - warming story of friendship and mutual respect.
One common theme is the growth of their relationship. They start to understand each other better. Another theme is power - up. They gain new abilities or improve existing ones during the training.
Naruto would probably give Haku training on chakra control. Since Naruto has had to work hard on his own chakra control, he'd be able to pass on some useful tips. For example, he could teach Haku how to better focus his chakra for more precise attacks.
Naruto might become more in tune with the Kyuubi's power. He could access more of its chakra easily and use it more effectively in battle. For Hinata, she may gain a new sense of boldness. The training could make her less shy and more assertive in combat situations.