I cannot agree with this more. Coincidentally, I'm also fluent in German and English, and am learning Japanese.
At school, I took French, but I hated it. It only clicked when I went on an exchange, although I never kept it up. With English it was easier to pick up because of TV, films and games. But I only got good at it when I moved to the UK. The same with Japanese. Made almost no (real) progress until I went to Japan, and started using what I'd learned. Sure, learning the alphabet first helps, but language relies on being spoken IMO.
If you can, take a chance and just move to a country that speaks the language you want to learn.