Well, Naruto could start by observing his surroundings. For example, he might notice the way water flows in a stream and use that inspiration to create a water - based jutsu. He has a lot of chakra, so he could also combine his chakra nature with his unique experiences. Like when he was training with Jiraiya, he learned about the toad - related techniques. He could take elements from those and add his own spin. Maybe mix the rasengan concept with some new chakra manipulation based on his time with the toads.
One possible powerful jutsu he could create is a time - freezing jutsu. This would allow Naruto to stop his opponents in their tracks, giving him the opportunity to either land a decisive blow or set up a more complex strategy. Since Naruto has always been about speed and surprise, this jutsu would add another dimension to his combat style.
If Naruto creates a very powerful and dangerous jutsu, some characters might be afraid of him. For example, the villagers who were once suspicious of his Nine - Tails power could again start to fear him. However, his close friends like Sasuke and Sakura would likely trust him and help him control and master the new jutsu.
In fanfic, Naruto may create his own jutsu based on his emotions. His strong will and never - give - up attitude can be translated into chakra - based techniques. For instance, when he's feeling extremely protective of someone, he channels that emotion into his chakra and creates a defensive jutsu. He also might draw inspiration from his memories. Remembering his training sessions with Jiraiya, he could take some of the basic techniques he learned and add his own twist to them, like adding a wind - element boost to a simple physical attack jutsu.
One key factor is his vast combat experience. After facing various enemies, he knows the weaknesses and strengths of different jutsus, which helps him create his own. Another factor is his ability to learn from others. He has trained with many great ninjas like Kakashi and Jiraiya, and he can pick up on their techniques and make them his own. Also, his strong bond with the Nine - Tails gives him access to a large amount of chakra and unique chakra properties that he can use in creating new jutsus.
Maybe he found some hidden scrolls left by his mother. These scrolls could have contained the details of her jutsu. Naruto, being the curious and determined ninja he is, would have studied these scrolls carefully and learned the jutsu.
Well, it could be the Uzumaki Chain jutsu. In the Naruto lore, the Uzumaki clan had some unique abilities and the chain jutsu was one of them. His mother Kushina was from the Uzumaki clan, so it's possible that's the jutsu he learned in the fanfiction.
Well, in many such fanfictions, Naruto might start learning his father's jutsu when he discovers some hidden scrolls or when a mentor who knew his father decides to teach him. Maybe it could be someone like Jiraiya who reveals some secrets about his father's techniques.
He could practice in secret locations where no one can see him. For example, in an abandoned cave or a hidden part of the forest. That way, no one will know about the new jutsu he's developing.
To create a jutsu in Naruto Jutsu Maker Fanfic, look at the existing jutsus for inspiration. Notice how they are named, what they do, and how they are used in battles. You could base your new jutsu on a character's personality or backstory. If your character has a connection to water, like growing up near a big lake, maybe the jutsu involves creating huge water serpents. Another aspect is the chakra consumption. Decide how much chakra your jutsu will use. If it's a very powerful jutsu, it should probably consume a lot of chakra, but you can also create some low - chakra - cost jutsus for quick and repeated use.