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!