The best way, I think, is to learn what language do you learn and do it with your hobby. I like watching movies, and I'm learning English too, so I watch English movies, with subtitle of course lol, and hear what the actors say then match it with the subtitle. So we can learn new words and know the pronunciation haha. You couls also listen to the music and read the lyric. Those are the cool way to learn, I think :D Hope it helps ;)

It depends of the level on you are, i think. but if us have some experiencies, talking with peoples how know your new language is the best way for me.

Listening alot then speaking. Practice all the time.