The best way to become a music expert is to begin actively listening to music. Actively listening is doing nothing but focusing on the music hitting your ears.
Before listening to the song next time, try to remember as much as you can about it.
Listen to the song and focus on these parts you remembered.
Now listen to the song a second time – and try to focus on anything except those parts. Pick out the elements you couldn’t remember or didn’t realize were there.