Immersion
Thoughts on immersion and learning as a whole
In this section, I would like to discuss immersion as a whole. Some pitfalls, some tips and hopefully some encouragement.
How can I get a Japanese routine going?
I suggest not spending more time on Anki than necessary, and spending the rest of your time studying grammar, reading or listening. Ideally, get progressively more difficult reading and listening materials and keep on grinding. It really is that simple. This is both reassuring and demotivating: There is only one trick, and it works every time, but it requires dedication. The best way to setup a routine is to use (micro)habits, a concept I learned from this book. Start with simple habits and build on them progressively. The goal is to get used to having Japanese as a part of your life, not to burn out learning all the kana in one day just to get to reading faster. If you can that's great, but it's not necessary. Instead, take your time.
Immersion gets easier over time
Your first reading material is going to suck. You will spend a lot of time on basic grammar patterns. Almost every single sentence you will encounter will have one or multiple new words. This is normal. The key is to trust the process: The more you read, the easier it becomes.
Similarly, the first time you sit down in front of a drama episode, it will probably going to be difficult. People talk fast, the video doesn't necessary help you that much and your ear is not very well-developed yet. As you keep doing it and as you get better at reading, your listening ability will grow as well. Both reading and listening are important skills to have and you should polish them both.
Is it bad to do output early on?
It's only bad if you don't understand what you are outputting and have no way of checking that what you are saying (or writing) is correct. This means that corrected output is good at every stage of the learning process. What is bad is forcing students to output early on and this is what Krashen talked about. The myth that output is bad has nothing to do with Krashen's input hypothesis and seems to stem from this infamous article. That being said, input is still the primary driver of your understanding. If you don't know the word "wheel", then you cannot really use it in a sentence.
Are textbooks inherently bad?
No! Many textbooks are well made, but they are not replacements for doing the hard work. You still need to read and listen a whole lot to acquire the language. If you find a textbook you genuinely like, give it a go, but don't forget to immerse a lot. I personally like the Basic Kanji Book, Tobira and more generally the 新完全マスター series, especially for JLPT preparation.
On the topic of motivation
There will be days when you just don't want to read. This happens to everyone. Motivation is a powerful drive to start doing things, but it is usually not enough since it can fade away with time. What I suggest is to turn immersion into a routine, something you do everyday without thinking too much about it. The same is true for Anki. After doing it for a few months, Anki fatigue can start to settle in and you will possibly find your time reviewing cards to be quite boring. This is when having a proper routine in place will help tremendously, as you will just do it naturally, in the same way that when faced with a door you have to go through, you don't think for a minute on the right course of action; you simply open the door.
To summarize, it is necessary to be very interested your reading materials and to then use that excitement to get into a daily habit of reading. It is this daily exposure that will ensure your continued success.
On the choice of your immersion materials
There are many different kinds of native content you can use for immersion. Here are a few popular ones: visual novels, (light) novels, (YouTube) videos, Japanese TV, podcasts, music, video games. The best one will be the one you don't mind spending lots of time on. I suggest picking up two at the very least: a reading-based one and a listening-based one. Of all the choices above, my favorite for a beginner is visual novels.
The reason I prefer visual novels over basically any other kind of medium is due to how complete it is: you get a picture, a complete sentence and voiced audio (usually) at the same time, so it's nice to look at, you are reading and listening at the same time and the progress is easy to track due to the game nature of a visual novel (usually abbreviated VN). One big caveat is that most visual novels are for adults due to varying amounts of sexual content in them. Some very popular visual novels have none, and there are all-ages version as well. Overall, visual novels are fun, exciting and great for immersion. On that note, do notice that most visual novels will require you to run them with a Japanese locale. You can use Locale Emulator to avoid changing your system settings or you can create shortcuts with this tool.
This is not to say that other immersion materials are bad however, quite the opposite in fact. Ideally, you would expose yourself to a wide variety of Japanese reading and listening, from visual novels and Wikipedia articles to classics, anime and newspaper articles. But if you are going to choose only one thing for your reading needs, I'd make it visual novels (provided you like them). Remember, the most important part is interest, otherwise it will be extremely hard to make reading a habit. Moving on.
On the topic of pitch accent
You may or may not know that Japanese is a pitch-based language. This means that words have a certain pitch associated to them. While it is important, there is no need to stress out over it. Unless you're tone deaf (in which case you can train it a bit at the beginning), we will have pitch accent on the Anki cards we are going to use. You shouldn't fail an Anki card just because you did the wrong pitch. Instead, simply re-read the word with correct pitch and move on. Provided you listen enough, you will hear pitch and will be able to replicate it. That being said, I highly suggest you train pitch early on if it is important to you. A wonderful website where you can learn all things pitch accent can be found here. I highly suggest you start by watching this video made by Darius, a great contributor to the Japanese community.
Is studying grammar even worth it?
This question is more profound than it looks. Gaining a deep and meaningful mastery of a language requires recognizing the structures that are inherent to that language. Grammar helps you familiarize yourself with them. It also gives you vocabulary to discuss these structures. That being said, it is only through practical use of the language (be it via input or output) that you will truly internalize them and become fluent. In other words, grammar is useful because it lets us articulate how and why the language works, but it is not actually the language per se: It is simply an analysis of the inner workings of the language. What this means for most people is that we should be familiar with basic grammar patterns at the very least, with further grammar study done periodically as one encounters new grammar structures through immersion. Nothing wrong with going all in with grammar either and reading everything in IMABI though. Likewise, while not necessary to be fluent at all, knowing some basic classical Japanese can inform certain modern structures, for instance why is が acting like の in the phrase 我が国?
Is it okay to watch anime with non-Japanese subtitles?
Sure, why not. Just make sure that you're actually listening to the Japanese and not spending all your time reading the subtitles. If all you're doing is reading English subtitles, then you're not actively immersing in the language. I actually suggest using Japanese subtitles though, because it's fun, it gets you better at reading Japanese and it's still great to help you understand what's being said. You can also have both and only glance at the English subtitle from time to time if you're totally lost. But don't compare the translation to the original, it'll most likely be way off.
What are some details I might not be aware that might help my Japanese learning journey?
Sleep enough. Stay hydrated. Get fresh air. Do some exercise. These four things are some of the most important things you can do for yourself more generally. Not enough sleep or hydration causes headaches which many immersion learners have talked about while reading. Similarly, fresh air and walking can really boost your brain capacity to acquire new information. More generally, exercise boosts your cognitive abilities. Just as important is getting adequate sleep because even relatively moderate sleep restriction can seriously impair waking neurobehavioral functions in healthy adults. I recommend getting at least 7 hours, ideally 8. If you're a teenager, get at the very least 8 hours of sleep if you can. Likewise, doing Anki or reading when you're fresh can really help.
Avoid toxic arguments regarding study methods
If you hang around in Japanese learning communities, you are bound to see an argument regarding the efficiency of one method over another. While it is important to update our learning methods as time passes and new information becomes available, haranguing people over it is not worth your time. My opinion on the matter is that while there is such a thing as a best method for an individual, that doesn't mean it's best for everyone. Some people prefer textbooks, some like anime, some prefer tutoring. The method presented on this one is one method that worked best for me and for the majority of people I have encountered, but it can (and it should) be tweaked to your own personal preference. No, it is not "cheating" to use textbooks, or to study kanji in isolation, or to read from a dictionary.
Is it stupid to mine words from a dictionary?
No. If you like reading the dictionary, read the dictionary. If you find cool words in it and you wanna add them to Anki, that's great.
Passive and active listening
Passive listening is listening to the language without paying active attention to what you're listening to. It is not entirely clear to what extent passive listening helps you learn languages. It is however pretty clear that active listening does help, however. Active listening requires you to focus on what is being said and to try to properly understand what is going on. You might argue that passive listening can get you better at recognizing the sounds of the language, but many people sing in other languages and their pronunciation is closer to Animal Crossing's Animalese language than to proper pronunciation. You might then argue that input is not output, but at this point we're both confused and not sure what to do so we drop the argument and conclude that you should do passive listening if you like it, but you probably shouldn't expect to get massive listening gains from it.
Should I get Japanese classes or a tutor?
If you'd like to, but it's not necessary by any means. Getting a tutor to correct your pitch accent would be a really good idea if you're interested in having really good pitch accent.
I feel like I'm reading too slowly!
Read this. The TL;DR is that you should read more. Actually, this is almost always the solution to any Japanese-learning problem you might encounter!