Musicality: I'm of the belief that you either have it or you don't. As a follower, I find it excruciating when my leader can't find the beat of the music, much less interpret the melody in a creative way. But I understand that some people struggle with this, so I was pleased when I found someone creating videos for visual learners. Here's one, teaching the difference between tango, milonga and vals beats:
See more videos like this here.