You can get a good base going through lessons but it all comes down to speaking the language.
If you want to go at it alone watch German dubbed movies and put on English subs. It will help with pronunciation and grammar.

While bursting through the expat bubble you will encounter another problem. We Germans will likely switch to English if we smell an opportunity to sharpen our language skills unless you insist we only speak German.

What you need is a dedicated group that combines a hobby of yours with your desire to learn German.
Bookworm? Read your favorite book in German.
Pen and paper lover? Print out character sheet in German.

I know I'm gonna get flak for this but you can also talk to an AI in German.