Basically for any languages on this world, you just need to take care of the 4 following aspects for mastery: listen, speak, read, write. To put it simply is to ensure input and output, listening and reading are inputs, speaking and writing are outputs, of which listening complements speaking, and reading complements writing. This has to be done daily, no shortcuts!
Listen: Conversations or dialogues, radio broadcasts, popular songs, audio stories, podcasts etc. Listen attentively, analyse contents, recognise characters.
Speak: Talking to other people who can be your parents, siblings, teachers, seniors, mentors, strangers etc. Read aloud passages, stories, novels, proses etc. Pay attention to pronunciation, take note on rate of speech, learn and use on the ground.
Read: Books, magazines, newspapers, comics, reference books, song lyrics, subtitles, scripts, poems, advertisements, signboards etc. Make a note on unknown words, internalise sentence structures, understand both the superficial and hidden meanings.
Write: Dairies, journals, essays, stories, blog posts, proses, greeting cards, text messages, letters etc. Have a clear train of thought, paraphrase accordingly, use good words and phrases whenever possible.