Be prepared to put in the work, honestly. You’ll hear of magic bullets and 90 days to fluency and honestly it’s bullshit. Why do you want to learn another language, and what do you want to use it for? These sound the same, but they aren’t. I’ve lived in the Netherlands for three and a half years now and I am still nowhere close to fluent. I can get by, I don’t have a problem in shops or cafes, but I can’t always find the words I need and end up talking around the problem. I’m like a four year old trapped in an adult’s mind, almost. Or maybe the other way around. So be prepared to be frustrated!
Before we came here I hit Duolingo hard, maybe three months before? It’s good for building your vocabulary quickly, and for setting out some useful phrases, but it has its limitations.
We started with lessons two weeks after we got here, which we’re still doing. I thought I’d be fluent after a year! Ha!
Babbel is a good app once you have a bit of grounding, for instant recall. You will need that if you’re ever planning on speaking to people! I don’t really get on with the app, though.
Netflix with subtitles is good, and that works both ways! Archer with Dutch subtitles is often unintentionally hilarious.
What are you really knowledgeable about? Grab some magazines or books on the subject in your chosen language. Likewise your favourite books – see if there’s a translation and get stuck in. Tintin is excellent in this respect – it’s a comic and it’s been translated into pretty much every major language, so you can have the English and your target language next to each other, panel by panel.
There are definitely more things to try, but that’s a good starter for now! Good luck. It’s tough, but soooooo rewarding.