If I could D-Mail (Steins;Gate reference) the young me some advice, this would be it.

You gotta know Katakana, here's the best book I've got. https://a.co/d/7ifbD9W Starting right now, commit not to ever use romaji unless a Japanese person would be using it.

Next, make flashcards of and memorize everything on the "Japanese Grammar Review Card" image I'm including pictures of. I know it's a lot. This is all the grammar covered in the first two years of American high school Japanese classes. If you know this much, you're basically conversational. This also also covers most questions you'll have about conjugation.

Listening
- Doraemon is the best kids show. Kids rewatch episodes and quote the shows they like. Try to do this.
- Podcast: Nihongo Con Teppei. It's the best beginner podcast I know of. Start here. There's LOADS of content. It's all super short and clear and fun.

You need to learn to write kanji
That's the only way to proficiently learn to read it. And Kanji gives you the clearest view into how Japanese works. I've linked the best beginners kanji book out there. Unlike some conventional Japanese courses, this one teaches the kanji which are composed of radicals first, so that as it advances you alredady know the small pieces that you're using to build up new kanji characters. This makes it much easier to remember stroke order and meaning. It also makes it very easy to use visual memory devices to remember kanji. Additionally, the kanji are grouped into topics like "animals" and each kanji has 5 example words. So you can just use these as your vocab flashcards too. When you've worked through this book, you'll be able to pass the JLPT N5 and N4. You'll also have the skills to learn the rest of the kanji you want. https://a.co/d/bjryIlN

Download HelloTalk (you don't need a private tutor if you have friends)
- Include a detailed bio, profile pic, and be honest in there but try to make yourself look interesting. Include as many interests as you can. This is not a dating app. You're here to make friends with every not creepy person on there. Be a good listener. Be polite.
- Post to it twice every day. Morning post and evening post. First type what you want to say in English. Then, above the English, translate it into Japanese as best you can (try to do from your head, but it's ok to reference dicitonaries.) Hit the record button and read your entire post outloud. This can be embarrassing for beginners, but it is the most important part for learning and making friends. Lastly, if you want attention each post needs a picture. Can be your cat, a flower outside your house, your coffee (the picture can also help you decide what to post. Tag every post with "please correct me."
- Search the tag "please correct me" and spend 5-10 minutes liking and correcting every single post you can. Comment on the posts in English and Japanese. Follow people whose accounts look interesting.
- Japanese people are constantly saying "does someone want to do a video call?" Respond to those. They almost always mean "right now" so be prepared for that. Maybe just do one a week, or one a day, whatever you can handle. You'll have to spend at least half the time speaking English, but you're good at that and it'll make people like you.
- Within a month you'll have almost 100 followers. There'll be a dozen Japanese people in your life that you can easily ask for help and it won't be awkward or feel demanding.

Chatting to yourself
- Daily. Take a stroll and record yourself speaking in Japanese about the things you've consumed lately. Like Doraemon or Nihongo Con Teppei. Try to let your mind wander. And try to communicate ideas with the limited Japanese you have.
- When you get home, listen to your recording. This will help you notice mistakes that you "know" not to make, but will make in conversations. This also gives you time to look up words about the things you enjoy talking about. Make flashcards, etc. You can even write questions to take to HelloTalk.

THE Grammar book: https://a.co/d/43x463H
- This is just the best book out there. It's "beginners" but could easily take you 6 months to 3 years to study depending on your pace. If you ONLY learn this book, (and of course talk with Japanese people regularly,) you can get conversational.
- One of my most effective study methods here was choosing one of the uses for one grammar principle, reading the section about it, and making flashcard with an example sentence, and using it all throughout the day.

You will need flashcards. And you want Anki
It's free. I know it doesn't look pretty, but every other flashcard app I've come across is either horribly programmed, ridiculously priced per month, or both. And Anki is just based on text files, so you'll never lose your information. Every other app gets out of sync, loses data, overwrites data, and will get outdated as soon as it isn't profitable enough, and could move to a monthly payment system at any moment. For example, I have thousands of flashcards on Quizlet that I can't access anymore because of their pricing schemes. Anki is the one app that won't screw you over within 2 years. It's open source. It's highly customizable with just a little bit of knowledge. Spend a week getting good at Anki and you will have a much easier time learning anything including Japanese from here on out. It's scheduling system is phenominal. Use Anki.

Learning vocabulary
- This one is more arbitrary. https://japanesetest4you.com/ has vocab lists and practice exams for the JLPT (Japanese proficiency tests.) Start with N5 (the lowest level) and start making flashcards.
- I would recommend finding lists of things you want to learn such as Reddit posts on "Naruto vocabulary" (or My Hero or Demon Slayer or whatever you watch if that's the kind of stuff you want to learn haha.) Just know studying fantastical anime isn't going to help you be conversational until you know normal conversation first.

General tips:
- In English, we pretend to understand everything people are saying even when we only catch like 60% of it. Your Japanese will only get good when you embrace this. Don't look up words during conversations, podcasts, songs, or TV unless you have heard the same word 5 times in context and you still aren't sure what it means. When you do finally look it up, you'll definitely remember that one. (The first of these for me was "kamo shiremasen"
- The best language learners BY FAR are those who just launch into a sentence even if they aren't quite sure how to say it. You have to grow that part of your brain that simply is in Japanese. You don't want to be translating in your head forever (though you have to start there.)
- You will be petrified and won't be able to learn unless you can laugh at your mistakes with others. Like when someone says "chotto okashii" when you say something silly. Also, if you laugh and say something like "nihongo ga taberenai" people will love talking to you. Being perceived as a loveable kid is preferable to being seen as an prideful yet incompetent adult. You want people to take you under their wing.
- Duolingo can be useful as a supplement to these other methods. You'll learn words and hear Japanese sentences naturally spoken, and they'll be broken down into understandable bits for you. It just sucks if it is your only method.
- Learning polite Japanese is important. Learning casual Japanese is more important. If you learn to speak like a kid you'll catch on to the grammar 10000x faster. I spent 2 years only speaking "masu" and "desu" and it stunted my ability to conjugate and speak in casual settings.
- Stop saying the subject so much. English requires you start sentences with a subject. "I went to the your mom's." "I wiped my butt" etc. In Japanese, subject is implied until someone changes it. Honestly, it's usually just implied anyway. Think "Wiped butt" not "i wiped my butt".
- Japanese is based on particles. wa (spelled ha), ga, wo, to, ya, na, etc. Particle comes after a word. And it gives meaning to that word. "Watashi wa" says watashi is a word and it is the subject.
- Outside of particles, you combine words with unconjugated verbs. "suru" for example means "to do." So "jump-suru" means "to jump". You'll often hear Japanese sentences chain human identifiers at the end of a verb, like "jump suru hito" or "the jumping person"/"the person who jumps"
- You'll solidify all this and more as you dig into the grammar book.