Good musicality brings out unique elements of songs. At a very high level, the dancers can actually cause you to hear things in the song that you weren’t aware of before. This ability rests on two primary skills: knowledge of music, and especially unique features about the particular song, on the one hand, and the ability to bring out different layers of the song in your dancing. This exercise is designed to develop the latter skill.
The Drill: Without a partner, put on a song that has lots of musical layers. A straightforward song that has layers is I Gotta Feeling by The Black-Eyed Peas; you can hear new instruments or voices coming in at the start of each phrase for the first half of the song. More complicated (and hence more interesting) layered songs include Billie Jean (the original version by Michael Jackson) and Cantaloop (Flip Fantasia) by Us3.
Listen through the song and focus on identifying different instruments, voices, and rhythm patterns. In Billie Jean, for instance, you have the eighth-note rhythms on the drums with the down-up emphasis, the bass rhythm, the synthesizer “dum, dum” rhythm, Michael’s voice, the repeated accented rhythm when he sings, “movie scene,” (“caused a scene,” etc.), the rush-and-pause rhythm when he sings, “one will dance / on the floor / in the round” (etc.), the bridge, the chorus—and that’s just scratching the surface of this song.
Once you’ve listened through the song a couple of times and feel comfortable identifying the layers of the song, put it on again and start dancing to a specific layer. Don’t try to dance west coast swing at this point; instead, freestyle dance in order to see what you can do that fits the chosen layer. Play with footwork, body isolations, moving around, arm movements, or any other aspects of your dance. The goal is to find movements within your body that fit the layer.
Keep working through each layer, finding your dance elements that work for the layer. Build up a repertoire of ways to freestyle dance to each rhythm/instrument/voice. When you are comfortable freestyle dancing, you can practice dancing your basic while incorporating those elements.