For language, I have lots of success through the use of structured frameworks, namely conjugation tables, sentence structure, and vocabulary. With those three things you can create a lookup table in your mind and start using the language until it becomes more automatic. If you’re using online tools (Duolingo-types) it’s easy to fall into the gamified app trap and never actually speak. One must vocalize the things one is learning in order for the language to also be processed along the vocal path. This can be done in nearly any way as long as the words are being said out loud, in a normal speaking voice. Do this in those gamified apps by speaking out loud in the target language (always the target language!) prior to writing or submitting the answer.
Finally, there is no replacement for speaking with a native speaker. You’ll get genuine responses, cultural context, and compliments. People love hearing other speaking their native tongue.