And if something is too easy (like the basic conversations) then move on to something harder. If you can understand everything and you're making no mistakes, you're not learning!

The best way to be fluent in any language is immersion. It won't happen immediately but speak English at any time you can, try to think in English and even have conversations with yourself if you must.

First study really hard so you know enough to have conversations and read books (you seem to have done that already). Then get as much exposure to the language as possible: read books, watch movies, talk to people, change all your software and websites to that language (but avoid things like Youtube comments)... You can keep learning words, but don't do only that. Don't skimp over surprising things but ask why it's different from what you expected. The more feedback you get about your mistakes, the better!