I haven't personally used LingQ, but it seems to be the best way to pick up new languages. It provides a feed of news in other languages with a neat vocab tracker! I haven't learned a language with it yet, but I'm very interested. There's also an excellent interview with LingQ's creator.
---
[1] https://www.lingq.com/en/
[2] https://www.youtube.com/watch?v=TKg23ZFURX0