My method:
1. Find language to learn, example: Korean
2. Write/Spam only Hangul in notepad 2h/daily
3. After two or three months of this you shoul well know Hangul so find like 20 words and spam/write it in notepad and try to speak the words and spam it to remember.
4. Do it same with more and more words..
5. When you will know many words after year, find good book with grammar, listen music in this language, movies or join to language school and practice next 1 year. or just use android apps to learn.. best apps to learn is with ranking or exprience because you will want to be best

I did like this...

Do it same with any language you want. Want Chinese? learn first Chinese letters and same with Japanesse etc.. if you want to learn German, Spain or other with ABC letters it's more easy because you doesn't care about diffrent letters so 1. is off

But best and always best will be just... SPEAK WITH NATIVE SPEAKER and learn from native. That's easy question.