Ask HN: What are your language (human, not programming lang) learning hacks?

Other than physically moving abroad, what are your language learning hacks?

I'm currently making a list of English words that I commonly use everyday. Hoping to use that as a base to learn French vocabulary (I understand this will only help with vocab, not grammar etc). Anyone tried this? Does it work?

Any other tricks, hacks etc to learn a foreign language and retain, starting from scratch, for adults?