Plot = 5.8: This far, I don't really see much in the way of the plot. What is the point of this story? Is it an Avatar story? Will another war spark and Naomi joins in? After finishing the released chapters, I looked at the main page and discovered that this is a character-driven story. That in itself is not a bad thing, however I'll elaborate on why it doesn't really work in this one in the next category.
Characterisation = 4.2: Unfortunately, the characterisation could not be a higher score simply because I found myself question who these people are. I feel like I know nothing about them. Naomi writes in a diary but it's literally just a summation of events; there are no thoughts or feelings that could help the readers get a firmer grasp of who she actually is. I don't even know how old they are (and I refuse to read the main page because the story should tell me everything I need to know. Going back to the plot and how it's a character-driven story, because I don't understand the characters, it makes it incredibly difficult to stay focussed on the story. I simply don't care about what happens to them.
The ways in which the characters also interact with each other leaves a little to be desired. In chapter 12, Naomi states that she likes Ryoma 'more than a friend', however I've barely seen any friendship-liking by this stage. We, as readers, truly have no idea what is going on in their heads or why they do the things they do. When someone likes someone else, there are thoughts and physical reactions to it. As it stands, I feel as though it was a random 'annnnnd now I want romance. let's do romance', rather than an actual thought-out plot/character point. To be perfectly honest, I feel like Naomi and Kentaro have more of a connection if only because the relationship feels less forced.
Believability = 6.2: Dramatic stories (and dramatic parts of stories) are some of the most difficult to write because if you get it wrong, it seems too, well, dramatic. Unfortunately, that seems to be what occurs here, and part of the reason is that I don't understand the characters. After Naomi's [spoiler alert] father dies, her mother suddenly becomes violent and abusive, for no apparent reason other than 'she's grieving'. The narrator questions 'What's happening to mother?' and the reader can't help but agree. It makes it incredibly difficult to read the story when the only reason for it seems to be to get the main characters to leave their village. There could be many other reasons that flowed better with the story—there might be too many memories, or they need to go and find work. I personally dislike abusive parents in stories for the precise reason that 99% of the time, it's incredibly uncharacteristic.
There are also little things that make me question the story, too, such as noodles being more expensive than roast duck (must be made of gold or something), the fact that Ryoma had to tell Naomi to 'bow' and not shake his father's hand (I don't think anyone ever shook hands in ATLA—they always bowed, and the fact that Naomi is fairly cavalier in regard to telling people 'oh yeah, my mother is super abusive'. Usually, victims of abuse are really not very talkative about it unless it's to someone they trust (and even then). Naomi was 'afraid' Ryoma would ask why they were travelling, and yet she answers straight away, truthfully? Why was she afraid in the first place?
Technical writing = 7.9: Some passages seemed very choppy. The lack of connecting words or punctuation (and, because, however, therefore, etc. and commas and colons). There are also a number of instances in which a proper noun isn't capitalised (the most common one seems to be 'dad'. If you say 'my dad said', it isn't capitalised, however 'Dad said' is because it's being used as a name).
There is also an overuse of commas. A comma is used to indicate a pause (or a list) and using it too often, or in inappropriate places, is incredibly distracting as it causes the reader to trip over the writing, thus reducing how much we are immersed in it. Missing apostrophes is also an issue, but it's not as problematic because it doesn't happen as often.
Non-technical writing = 6.8: As always, this category is a little harder to judge. The reason for the deduction here stems primarily from the lack of flow mentioned above. There are many instances speckled throughout the story of pure action. "I did this. I did that. Then this happened".
This also leads to a lack of emotional depth. You're telling me that she's sad, but not showing me. I want to feel them crying. The pain in her chest as Naomi realises that her father is never coming home to her. He lied. He broke his promise to read her stories and teach her earthbending. He abandoned her and he's never going to be able to make it up to her.
Organisation = 7.3: This is fairly straightforward, just like the story, and there's really not a lot to say. The one thing was the lack of action (and I don't mean 'kya! tsate the steel of my blade, you bandit!). I mean the constant use of a dramatic even to further the plot. There seems to be no rhyme nor reason, and it does detract from the conventionalised 'orientation, rising action, climax, falling action, resolution. If one were to follow this, the story could be completed by the time Naomi arrived at Chin Village, because all the bases would be covered. However, it doesn't end there, and thus starts another mountain to climb up. It makes the reader wonder where the story is actually heading because the actions that occur could be completely random. It makes us wonder if the author knows where the story is heading, and that is not something a reader wants to wonder.
One other thing is the random introduction of the Avatar, Avatar Kentaro, in chapter 15. A new character should not be introduced halfway through a story—especially when there is already confusion as to who is the Avatar. In ATLA fanfic, an OC is the Avatar unless explicitly stated to be otherwise. It's a thing. In this story, it's problematic. The readers have no idea when this story is set, and without any talk of the Avatar in the preceding 14 chapters (+prologue), for all we know, it's Aang. Or Roku. Or any other Avatar. This throws off the reader and is just frustrating.
Total score = 6.36
My advice: Elaboration. Add more plot and character development and emotions. You have the bones of a story, now it just needs to be expanded upon. Most of the issues i found related to the characters, so focus on them, and it will definitely increase how immersive your story is. In short, we don't know enough about the characters, plot, or world.