In honor of seeing 5 more posts on reddit about 'best way to learn X language again':
Here's the guide on how to learn a language from r/language learning: https://www.reddit.com/r/languagelearning/wiki/guide
The answer to 'the best way to learn' is to find whatever study materials and study activities you can get yourself to do regularly for hundreds to thousands of hours, that will regularly teach you some new stuff and allow you to practice understanding some stuff you've learned. Ideally, study materials and study activities that focus on teaching how to do the things you wish to do in the language. (So if your goal is to speak about X topic, you eventually DO need to study listening, speaking, practice speaking with others, and learning vocabulary that comes up when speaking about X topic). You will notice that 'the best way to learn' is going to be different for different people! One person's answer may not be the 'best' way for you, only you can determine the 'best' way for you.
If you've never studied a language before, my personal opinion would be recommending you stop focusing on 'the best way to learn' and focus on structured language learning materials. If you've never studied a language before, never made your own study materials or collected them and planned your own study activities and scheduled your study time? Then I think it may be easier for you to just pick a study material that TELLS you what vocabulary and grammar to study, TELLS you what exercises to do to practice reading, writing, speaking, listening, and then just committing yourself to working through that study material 1-2 hours a day on average. You will want to pick a well made study material - such as a textbook many people recommend for that language for beginners, then for intermediate learners, or a class at a university/college, or a free online course that's equivalent to a college course (like on Coursera), or a well known language learning material that many people said worked well for them (Assimil, Teach Yourself, etc). If you're bad at figuring out what to study yourself, I recommend you pick a study material that teaches ALL 4 listening, speaking, reading, listening. So the study material should have audio and text, and you should do practice writing exercises based on grammar and vocabulary in each section, and practice speaking like the audio that is provided. The study material should also have 2000 words or more (if for beginners) and cover a variety of basic grammar, so that you're prepared to move to an intermediate study material when you're done. So while I love study materials like Language Transfer podcast, if you're a beginner who's never studied a language before, Language Transfer mainly focuses on grammar and listening skills... so if you aren't good at finding other resources for reading, and aren't good at making up your own writing/speaking exercises, then Language Transfer will not be ideal for you. If you pick multiple study materials (which will be a bit more difficult if you're bad at planning your own study plan), make sure the combination of those study materials covers overall beginner material (2000+ words and basic grammar) and writing, speaking, listening, reading skills.
Another option, if you've never studied a language before: find what someone else did and copy what they did. Is it the 'best' method? Depends on if you can get yourself to study regularly for hundreds to thousands of hours. What you can get yourself to do regularly, will be the best method for you. People share their methods online all the time, some name them (Refold, Mass Immersion Approach, Comprehensible Input, Automatic Language Growth, Assimil, Listening Reading Method), some people just share their study plans online. Choose to copy the study methods of people who've reached goals similar to what you want to do - so for example if your goal is to read in Chinese, copying the guide on Heavenly Path's Site for reading is likely to help you reach that goal. If you like learning by just listening/watching, Comprehensible Input methods like Dreaming Spanish may suit you well. My initial goal was to read in Chinese, so I looked up people who'd already done what I wanted to do, and read their study plans, and then studied the same materials they studied. It worked. Then I looked up how people improved listening skills, and again copied the study methods they did. If you know what your goals are - what you want to do in the language, you can just look up what other people did and find something that both would help you reach your goal AND that you can get yourself to do regularly.
In the end, my personal opinion is, it doesn't matter what the 'best' way to learn is... aside from whatever motivates you to study regularly. I've read a LOT personal experiences people have shared of their progress. For the most part, most people who put 2000 hours into studying a language end up with a similar level of skill. So just study the same amount of hours everyone else who accomplished your goal has studied, and your language abilities will end up similar to theirs.* (The only exception to this is: if you avoid studying the actual skill you wish to be able to do in the language, you will still EVENTUALLY need to put study hours into THAT SPECIFIC SKILL. I saw someone who studied 3000 hours with audiobooks and asked why they couldn't understand show dialogue... they knew the words, of course! They just had spent 0 hours practicing listening to the way people speak in shows, how they talk fast and less clearly compared to audiobooks. To get good at doing something specific... you need to spend some time DOING that specific thing. Or if you spend say 1000 hours like me reading chinese, then wonder why you can't understand an audiobook even though you know all the words? You still need to spend study hours LISTENING to audiobooks to get good at understanding them. So assuming you are spending your study time ON the actual activities you wish to do, then yes you'll reach similar language levels to others who studied toward that goal for X hundred or thousand hours. Also, depending on the languages you already know, and the language you're studying, will effect how many hundred or thousand hours you need to study - compare your progress to other people who know the same language and are studying the same language. A motivating little story: many people who study with Dreaming Spanish's comprehensible input lessons made for learners reach a ~B2 level after 2000 hours, starting to read after 600-800 hours and starting to speak after 1000 hours. There was a guy who studied French by watching TV shows without looking up the translations of any words, not necessarily comprehensible, and then after 1200 hours he started reading French, and after 1500 he started speaking, and after 2000 hours he passed a French B2 test. The Dreaming Spanish learners used videos made for learners, where they're made to be extremely easy for learners to guess what each word means. The guy who watched French shows could guess the meaning of some words in kids cartoons - but could not understand nearly as much as those DS learners using material made for learners - and then after several hundred hours moved to shows for adults. Both DS learners and the guy who used regular stuff for French native speakers, achieved similar abilities after 2000 hours. I would argue that a LOT of people would say the guy who studied French did it in a 'worse' way... since he did not look up translations which could have helped him understand more faster, and did not use videos intentionally made to be super understandable to learners like DS learners do. And yet, he achieved similar results. A lot of people who study with Refold method - tons of anki flashcards, looking up words while watching shows/reading - also have similar results. So I would say this is all a good example of: just pick whatever study method you can get yourself to do for thousands of hours. Eventually your results will be similar to people who've done other study methods anyway. So the 'best' method is simply whatever you can get yourself to DO REGULARLY.
