There is more to a song than just the underlying 4/4 time and finding the 1/2/3 depending on what beat one breaks on. There is the 2/3 or 3/2 clave, the cowbell, conga, maracas, piano, timbales, bass, bongos, guiro. In addition an instrument can play different rhythms. The more you can understand the song elements the better your dancing can get and one neat little tool that can help one understand more of these different elements is the SalsaBeatMachine. Check it out for yourself and see whether it can help you.