It seems I've forgotten to use this platform to tell people to use flashcards, particularly for language learning. Not Memrise or Duolingo, but something like Anki, as focused and rapid as you can make the process go. Make it a true test of recall instead of just an opportunity to recite something you wish you remember.

My current language learning flashcards (which I use to study Chinese) include cards for every Chinese character of note – both mapping them to a keyword related to their usage, and another card to their most standard pronunciation. I have cards for the meaning of words (although quite a bit fewer than I used to – it's probably good to cycle out vocabulary cards where the word's meaning is completely apparent from the characters, or when it's so common it isn't useful).

Most of my study time, though, is spent on listening cards, almost all of them created with a short program I wrote that, when I give it a Chinese language video and Chinese language subtitle file, produces a flashcard where I can hear the bit of dialog, see what's going on in the video (just a screenshot, to save the people generously running ankiweb the cost), and my goal is to understand what's being said. The answer side of the flashcard contains the Chinese subtitle text, and if that's not enough to understand it, I can create vocab cards, or add in a Chinese language description of what a word or phrase means, once I look it up. I have thousands of these cards, and the files to produce tens of thousands more. It's more than I could ever study unless I get truly fluent, and possibly enough material to get me there. I'd recommend a few different sources, at least one extemporaneous, and at least one nonfiction.

Obviously, you could have an English translation on the answer side if you're earlier in your learning process. If I was still there, I would change my script to allow me to give it English subtitles as well (you would not believe the tedium of data entry). But I am not. I wouldn't worry, bizarrely, as while English subtitles are easy enough to find, because Chinese is so regularly hardsubbed into video, the actual subtitle files are the hardest thing to get here.

In addition, I try to have a little mp3 player playing Chinese all the time, so I don't even have to start it to listen for a few seconds. I suspect this combination is probably the best for efficiency, but adding in more continuous focused listening is a good move. Try to follow along, and if you want more practice reading, you should probably watch Chinese TV with Chinese subtitles.

Try to build friendships with native speakers. Have actual conversations. Language exchange is a pretty useful experience, even though it can be terrifying and it's challenging to overcome the shame and embarrassment of it all. Courage is a valuable virtue, in that its dividends are more apparent than most. I have nothing to recommend except accepting failure and fear and acting anyway.

Chinese is hellaciously difficult to learn. Every once in a while my studying reaches an intensity where I vow my children will grow up speaking Esperanto as a first language. They won't suffer, unable to communicate, for any longer than absolutely necessary.

For the rest of us, it's worth meeting people where they are. You can teach your own child whichever languages you like, but strangers come as they are. I think learning languages is useful, if only for the humbling experience of truly being terrible at something as an adult. Few people take the time to be a beginner again, once they can avoid it.