Good concentration on the rhythm and the steps is essential as the steps and moves are changed often and suddenly in salsa dancing. There are several different salsa styles that all have different characteristics. In the Cuban styles the dance in taken place in a circle with the male dancer closer to the center of the circle than the female.
On the counts 1, 2, and 3, the male steps forward, replaces, and steps backward. On the counts 5, 6, and 7, the male steps backwards, replaces, and steps forward again. The female do the opposite. This gives for both of them the steps as left-right-left-pause/tap then right-left-right-pause/tap. The tap could be seen a small step that just help the dancer to follow the rhythm. It is often replaced with a pause.
The cross body styles are danced on a back and forth on a straight line. Salsa is a partner dance, but there are also solo steps. Solo salsa steps are often called shines. Shines are mostly show-offs and involve body movements and fancy footwork. Shines are more common in the cross body styles than in the Cuban style.
Source : http://www.articlesbase.com/art-articles/

