Listen to a lot of podcasts in that language, and read articles or news (they use more vocabulary you probably still don't know, that's why) and the last step is speak with native speakers about anything. I speak Spanish as native language, English on a high level and I've been practicing French for the past 3 months, so if you wanna practice let me know :)

Hi! Can we please practice french together!

Salut Anatoli, je suis french community tutor sur italki, je donne des cours sur le vin ou sur la cuisine française. A bientôt