Dan

Hi! This is a really great question that I definitely empathize with, so thanks for asking!

To be honest, in some ways, I'm pretty poorly equipped to answer this because I majored in Japanese in university and the bulk of my studying happened before a lot of the contemporary online resources for self-studiers came out. Which is to say, most of my learning happened in formal classroom settings both in the States and in Japan. I only did some self-directed learning towards the very end to delve into some JLPT N1 material that we just didn't have time to get to in my classes before I came back to the States.

So I'm going to break up the bulk of my actual answer into two parts. The one main suggestion I have in terms of proper resources is that if you're studying out of a formal textbook—which is perfectly valid! I think if I started even now, I'd still fare better that way than with the apps—it may be worth considering switching out to a different textbook and seeing if you take to its lesson structure and whatnot better. There are a handful of popular textbooks that people have pretty much always gravitated towards ever since I started studying back in 2008 myself and, to be honest, I'm not a big fan of how they do things at all. Maybe if I'd started out from scratch I would've had more success, but they've always had a lot of little things that I've taken issue with compared to how I was taught Japanese in the early years of the university. All of which is to say, if you're comfortable with textbook learning and willing to try something different, I would recommend the Yookoso series. It's really intended to be used in a classroom with a fluent teacher showing you the ropes, but I think it's pretty sensibly laid out for individual consumption and its methods of teaching grammar are less clinical since the focus is on building up learners' conversational expressiveness from the get-go. From what I gather these days, it's pretty easy to obtain using... whatever method you prefer, I'll say. If you want to be extra thorough, try tracking down the individual workbooks for each edition, too, which will give you more directed practice for each grammar point.

Now onto the more philosophical part of my answer. I obviously don't know what stage you're at in your studying. It sounds like fairly early on; not completely brand new, but still getting a real feel for the lay of the linguistic land, so to speak. My apologies if I'm completely off, but that's the impression I get from this sort of question. Either way, the sort of frustration that you're feeling is common among a lot of learners. Japanese is a fairly unique language, even among Asian ones that share some commonalities with it, so it's very normal in those early years for grammar progress in particular to come in fits and starts, especially among native English learners (again, sorry if I'm presuming incorrectly!). That's not to discourage anyone by any means; some of the most fluent non-native speakers I've ever known speak English as their first language! But I think it's important to dissect why it feels like grammar in particular can be tricky to come to grips with in order to figure out how to address those hurdles and set learners like yourself up for future success down the line.

I've been a Japanese speaker for about 16 years now and I've been working in it for 11, ever since I graduated university myself. And when I look back on that whole process now, I think with Japanese especially, in some ways, even more so than the kanji and vocabulary, the grammar is the true gateway to the language's overall worldview and philosophy, how it parses and portrays life around us. Of course, different people have different thoughts and different mentalities in day to day life, but as a linguistic framework, Japanese as a language views certain things in ways that are pretty distinctly different from other languages and especially western ones like English. That might sound obvious enough on paper given the difficulty that people like you can very understandably have with it, but I don't just mean in terms of obvious social and cultural dynamics that emerge from it. I'm talking about how certain things that we take for granted in terms of how we think about them and articulate them are straight up conceptualized at a foundational, fundamental level. I'll spare you the specifics since it seems like you're still a beginner and, by and large, the things I have in mind you don't really need to consciously grapple with until much later in your studies in order to succeed in these early stages. The main point that I'm trying to get at is, whereas we as English speakers can subconsciously take a lot of core, bedrock ideas and formulations for granted when learning, say, most popular European languages, Japanese, in a lot of ways, operates on some profoundly different paradigms at times. I don't say this to at all be discouraging or suggest that these paradigms are somehow impossible for people to pick up (in fact, I've seen non-natives who went on to have very successful careers here and they didn't start learning until they were in their 30s, 40s, or even 50s!). I only say this to frame the nature of the battle that we tend to have to wage when learning it, so to speak.

Which is to say, to me, learning Japanese grammar and internalizing it, really, truly getting it and reaching that point where it eventually feels natural to use and think in, is really about learning that different philosophy and those different paradigms little by little, step by step over the course of years. When people struggle to apply Japanese in earnest on their own and they see its rules and nuances as simply being incoherent and arbitrary, I think it's often because they haven't yet begun to internalize that philosophy and learn to see the world through those specific eyes. Rote memorization, while still helpful with grammar, tends to fail people in this exact regard because it creates this rigid mental expectation in terms of meaning and application based on the context and fluency level of the person at the time that they encounter that grammar point.

I'll give you one example of this that may well go above your head somewhat for now. Don't stress if some of what I'm about to say is new to you or doesn't make sense right away. I'm presenting this not with the expectation that you'll learn it right now from just me, but to just show you that Japanese is a language whose philosophical layers sometimes only fully reveal themselves after a lot of learning, even when it comes to the basics. So, when English speakers are taught verbal conjugations early on, they're often taught the verb ending ~ている/~ています is the Japanese equivalent of English gerunds, or words ending in ~ing and especially ~ing in the sense of something being actively done right now. In that mindset, 走っている correlates to "running" like "Haruka is running around the block." 食べている correlates to "eating" like "Kaoru is eating udon in the cafeteria." 話している correlates to "talking" like "Tsukasa is talking to Takahashi-sensei in her office." And so on and so forth.

That's all true, but it's not exclusively true with real world Japanese, either. ~ている is also used to express other temporal statuses, which becomes clearer and clearer the longer you're exposed to the language. I might say to my doctor, 「アスピリンを飲んでいます」 ("I'm taking aspirin.") even though I'm not taking any aspirin right at that moment. Or I might say to my coworker, 「クリスマスに家族と一緒に北海道へ旅行しています」to explain how I travel to Hokkaido for Christmas with my family, even though we're having this conversation in the middle of July. And most intriguingly of all, an article might describe a famous retired game developer by saying 「ファイナルファンタジーの3作品の開発に参加しています」, even though their work on the Final Fantasy series happened completely in the past! What gives? How can ~ている actually encompass all of these different points in time when English needs multiple different tenses to express them? It's because ~ている isn't truly just an ~ing equivalent. (In fact, there are other Japanese grammar points that I translate as English gerunds in my own work more often.) ~ている is, to put it somewhat simply, more of a statement of continuity. I have been taking aspirin lately and will continue to do so. I go to Hokkaido for Christimas every year because it's an ongoing tradition. And I once participated in those Final Fantasy games' developments, a factual truth that remains the case and remains relevant in practical effect today.

Again, I'm illustrating this not with the intention of giving you an impromptu lesson that I expect you to master right now. What I'm trying to emphasize is that, to a degree, successful language learning and thriving in that other language in the long term is about internalizing that philosophy over time in small, digestible pieces and that's particularly true for us English speakers when it comes to Japanese. When you do that, when you start seeing grammar not just as a mechanical means of expression, but as an articulation of an entire philosophy and how people speaking the language relate to our world, that's when things that appear nonsenical or contradictory or simply hard to learn and internalize begin to fall in place and the language properly congeals in our minds into something as cohesive and intuitive as what we natively speak.

Everybody who genuinely commits to learning Japanese for the long haul gets to that point in their own time and in their own way. My very succinct short-term advice for people like who might still be starting off—and by short-term, I mean possibly even for the first couple of years depending on the pace of progress and how much time you can realistically invest into your studies as an adult—is basically not to stress the brick wall moments with the grammar too much in the here and now. The philosophical comprehension will come with time as you learn more and more of the language and, again, a lot of that bigger picture stuff isn't really an urgent necessity to learn, especially for achieving basic communication for day-to-day matters like shopping and whatnot. What I did as a learner pretty much my entire university career from the very beginning, though, and what I imagine is helpful for most anyone is, just keep experimenting and iterating upon and applying what you're learning as you pick it up, even if you end up making mistakes and getting corrected along the way. The corrections will ultimately help clue you in to the philosophical underpinnings that make the grammar and everything else tic, even if that insight is of limited use in the moment. In my case, what I always did as a learner when I was studying new grammar in my textbooks and classes was, I'd copy by hand any example sentences that were presented to me, word for word, kanji by kanji. Then I'd write some more sentences of my own remixing those examples. And eventually I would write completely original sentences using that grammar to try and really hammer in those points. Of course, I'd also regularly mix in other stuff that I'd previously learned to keep that fresh in my memory and learn how they can relate to the new grammar, too. After all, Japanese in the real world is as fresh and dynamic of a language as anything else that's spoken, so it's important to treat everything you learn as fluid, relative things that can build upon and bounce off one another in improvised, sometimes even "emergent" ways, to put it in game-y terms.

In the longer term, my broader advice for learning grammar is to always learn new grammar with a willingness to interrogate it. Learn what you can from how they're formally presented in your materials, of course, but try to do so with a probing eye. Don't take what you learn now as the only way that grammar can be used and applied, but as just one approach. Most likely, it'll be the main approach that you're taught and maybe it's the approach that everyone uses when deploying it 99.9% of the time. But when you encounter potential disparities in meaning through your perspective as an English speaker specifically, take that step back and consider, like with my ~ている example up above, how that grammar can mean different things in different situations. Hypothesize what the root idea that could inspire those branches might be. It takes a willingness to imagine, especially what a language can be and you have to imagine what sorts of questions its evolution has had to answer in ways that go beyond how you've considered the idea of "language" as an English speaker specifically. Start looking up definitions of Japanese words and grammar in Japanese dictionaries and whatnot online once you've got the basics down pat and start feeling adventurous in your studies, and then broaden your studies from there to incorporate more and more natively written material. (It exists! Pretty much all of my studying after my second year was done exclusively in Japanese with Japanese learning materials written specifically for second-language speakers. It's out there and is what really helped my fluency take off and make all of this possible.)

In practical terms, a lot of these things are stuff that a professional linguist or a highly qualified teacher might be capable of answering. But Japanese in the real world isn't just whatever academia makes it out to be and so in practice, that philosophy is best discovered on your own and at your own pace. I assume you're not me and under the time pressure of a degree and graduation; if you really take to Japanese, you've got your whole life to learn these things, so any struggle in the here and now is perfectly okay. I've been professionally translating for over a decade and I still uncover new layers that deepen my understanding and appreciation even now!

I know that's a really, really long answer with a lot of super heady ideas that might be difficult to put to much use at this stage in your learning. I'm genuinely sorry about that! I know you wanted something more concrete about resources to turn to, which is why I highly encourage anyone else reading this to comment with their own suggestions and advice. Because like I said, I mostly studied this language when the "process" itself was largely in a very different time and place. While nothing that I did can't inherently work today, I'm also just not very savvy on what's available because, y'know, obviously it's not the sort of support I typically need now.

The one last thing I'll share is that while it is important to eventually get the fundamentals down pat in order to properly thrive with more advanced stuff, at the end of the day, everybody has different strengths and weaknesses when it comes to the grammar with any language, and that includes native Japanese speakers with their own language. In the real world, not all grammar points are going to be as equally important and relevant in daily living and, ultimately, people tend to gravitate towards what they ultimately need to express themselves and go about their business in a satisfactory manner. Even though I took classes on JLPT N1 material and don't regret learning that material for a minute, especially as a translator, a lot of natives will look at that material with some incredulity. They might recognize it in an academic sense as material that they studied in their own kokugo classes (国語, literally the "national language," the term used to refer to studying Japanese in school like what we mean when we say English class), but not something that they ever encounter or see anyone express in their own lived experience of the language. And that goes for non-native speakers like myself who use Japanese daily, too; we all have different sets of grammar that we need to rely on more often than others to survive and beyond that, our proficiency with other grammar points can vary, and that's okay.

Basically, from one person who started studying as an adult to another, it's crucial to bear in mind that for us, when it comes to that philosophical stuff and whatnot that I'm describing, we're playing literal decades of catch up in trying to learn these things. We spent those previous years learning how the world works in our native language first, so of course it's going to take time for things to click in another language and that struggle is okay and valid. Plenty of people have experienced it before, myself included, and plenty of people will in the future. Just try to maintain an inquisitive spirit about the grammar in particular, set incremental goals for yourself for what you want to achieve with it that you can reasonably set your sights on throughout your studies (eg: reading a particular manga, playing a particular game, watching a particular show without subtitles, etc.), and go from there. Again, you've got your whole life to work this stuff out; road bumps will happen, the speed you progress will sometimes shift, but it doesn't mean you don't have what it takes to master this stuff eventually no matter how old you are.

All of which is to say, good luck! You've got this and you'll be looking at whatever you're struggling with in the mirror before you know it!