(I'm learning English so sorry about any mistakes I may have made.)

I'd recommend you to study texts with audio in your target language (at least in the begining). After you have studied a bunch of them you will be able to listen and read authentic content (what I mean by 'authentic content' is a content that was made for speakers of the language). In this stage what you have to do to keep improving is: listen to authentic content at least one hour a day (initially it may be with subtitles) and use an app like Anki to learn roughly 10 sentences a day, each with one unknown word (here you don't need to study texts with audio anymore). After some months doing it you can start using monolingual dictionaries and studing pronunciation. When you feel that you are understanding the language well you can start practicing your speaking and writing. I didn't mention grammar here because it isn't a must and can baffles you in the begining. My recommendation is: when you feel the need for a grammatical explanation you look up, grammar shouldn't be your main worry. Well, I have been using this method for learning English for roughly 10 months now and it's working, although I'm not fluent yet, I know I'll get there eventually.