I’d like to weigh in because this is exactly what I’ve been doing for months now! I’ve found it more motivating to learn grammar as it comes up “in the wild” vs. to learn grammar through a textbook. The process is tedious, but it also feels really satisfying (to me, at least). Since you have a good foundation via Genki I, you should be in a good place to seek out grammar knowledge on your own. I have some resource recommendations and advice!
First, resources.
I’ve found the first few videos in Cure Dolly’s giant beginners playlist really helpful with just understanding the underlying mechanics of the language. Specifically, I watched up to lesson 16, but more can’t hurt. She discusses the different types of sentence structures, verb conjugations, and particles in a clear and succinct way that worked for me. Later on in the playlist, she also goes over a portion of an example story to show the thought process behind her understanding of Japanese.
You’ve already got japanesetest4you as a resource, but I have a few more that I kept coming back to a lot in the beginning:
-
Maggie Sensei’s website - blog with really simple explanations by a native Japanese speaker! What makes her blog stand out for me is that she goes over every single way the particular grammar point can be used on one page, including extremely casual speech (very important for manga) or somewhat atypical circumstances. On the other hand, she doesn’t use linguistic terminology and doesn’t always go into detail on why that grammar point is that way.
-
Imabi - on the other side of the spectrum, this is a website with incredibly detailed explanations. Although the author is not a native Japanese speaker, the explanations seem to be complete and correct (at least, according to what I’ve read from others - I’m certainly in no position to judge that). This is a great resource if you’re interested in knowing why a particular grammar point is the way it is. On the other hand, the explanations are very dry and very detailed, so it may take some working up to.
- ichi.moe - invaluable at the beginning, this website will help parse long lines of Japanese text into their individual grammatical parts. In the beginning, I had a really tough time knowing when a verb conjugation ended and the next part of the sentence began, or whether this kana is part of this word or a new word or a particle, etc. The parsing is not 100% perfect, but it brought me a long way in terms of getting used to the flow of Japanese writing. At this point, I consult it maybe once a week vs. almost every line in the beginning.
- A Dictionary of Basic Japanese Grammar (and presumably the rest of the series) - a physical book with grammar points listed from A to Z like a dictionary. I’ve only gotten this recently, but it provides some more in-depth grammar explanations that seem to work well for me. It throws around a lot of linguistic terminology (adverb, adjective etc.), which I like, and the explanations are more concise than Imabi. I like that it includes exceptions in each entry, and it also explains the difference between similar grammar points.
- DeepL Translate - generally better than Google translate, but try to avoid using either one as much as you can. Japanese is very difficult for an automated translation services like these because English and Japanese are just so fundamentally different. I use DeepL or Google Translate as a final check to make sure I’m on the right track sometimes, but you’re much much much better off consulting the English translation of Naruto that has been done by professionals. (though often a translator will completely re-write a line vs. translating from the Japanese literally - when this happens, you’ll at least know if you got the right gist)
- the Japanese stack exchange, hinative, etc. - sometimes, especially in the beginning, you just have to google it. I’ve found Stack Exchange extremely useful for contractions in casual speech for example. I couldn’t know a particular verb conjugation was actually a contraction, so I couldn’t just look it up using one of the other resources. Sometimes, you just don’t know what to search for. If you google the verb conjugation or whatever thing is stumping you + “explanation” (for example: “て form plus て explanation”), a Stack Exchange page might come up with the information you need to point you in the right direction.
- a tutor can also be helpful! There are tutors out there on websites like iTalki that will go through manga with you, but they do cost money.
I also have some advice. Don’t get too bogged down by understanding every sentence 100%. Learning a language is a process - and a long one at that! The goal here is to keep yourself reading and keep yourself learning. Trying to understand too much at once might result in burn-out and frustration. If a sentence is frustrating you, it’s okay to move on and come back to it later. In fact, I would recommend reading the same pages again a few days, weeks, or months later because you might be able to apply some new information to old sentences and reach a better understanding. That line that stumped you on page 1 may become clear (or at least clearer) by page 100 or page 1000. In fact, you will probably find that you misunderstood something the first time around, or you will pick up on additional nuances. That’s okay! It’s all part of the process. It’s also okay to reach out for help here on the forums - I believe the short grammar questions thread has already been linked!
Similarly, don’t worry too much about the translation itself. Your goal, for now, is to translate enough of the Japanese into English as you need to make sense of it, not to produce beautiful or even decent prose. It only needs to make sense to you. Of course, the eventual goal is to not have to translate anything at all, but some translation is helpful in the beginning. (I’m still in the translation phase myself).