First, give the OC a backstory that ties into the Uzumaki clan. For example, if they were exiled from the clan due to a misunderstanding. Also, give them some Uzumaki - like abilities like strong life force or sealing skills.
One great 'Naruto Uzumaki x OC Fanfiction' is 'The Hidden Leaf's New Hope'. It has a well - developed OC who teams up with Naruto on various missions. The story really delves into the OC's backstory and how it intersects with Naruto's journey. It also has some really cool fight scenes and character interactions that stay true to the Naruto universe.
Well, start with a strong concept for your OC. Maybe they have a secret past that ties into Naruto's future. Then, when writing their interactions with Naruto, show their emotions clearly. Are they in love? Are they just friends? As for the plot, it could involve a new threat to the Hidden Leaf that only the OC and Naruto can face together. Write vivid descriptions of the battles and the places they visit, like the training grounds or the Hokage's office.
A great plot could be that the OC Uzumaki is a healer. Naruto gets seriously injured in a battle, and she uses her Uzumaki healing abilities to save him. As a result, they become closer. Then, they find out that there is a conspiracy to eliminate all Uzumaki descendants. So they work together, using their combined skills and the power of the Uzumaki heritage to fight against this conspiracy.
First, you should focus on character development. For Naruto, keep his core traits like his determination and his love for his friends. For the OC, create a unique personality that can complement Naruto's. Also, include some of the Naruto universe elements like jutsus and the different villages. For example, the OC could be from a different village which adds an interesting dynamic.
He might also have the power to sense chakra more acutely. This would help him in detecting enemies from a distance, finding hidden traps that are chakra - based, and also in understanding the flow of chakra within his own body better. He could use this power to train more effectively and also to teach others about chakra control.
Well, he could start a family with Hinata and have lots of kids, passing on his Uzumaki bloodline. Then, he could encourage his friends who have some Uzumaki connection, like Karin, to also have families and pass on their Uzumaki genes. He could also set up a school or training center in the Uzumaki land, teaching the Uzumaki ways of life and ninjutsu, which would attract orphans or those who want to be part of the Uzumaki clan.
One idea could be a time - travel fanfiction. Naruto Uchiha (assuming it's an AU where Naruto has Uchiha heritage) somehow travels back in time and meets Kushina Uzumaki. They could form an unexpected friendship as he tries to protect her from the events that would lead to her death. He could also use his knowledge of the future to change things in the village for the better.