Understand the rhythmic structure of salsa (see resources). Salsa music is typically played in 4/4 time. The A clave is usually eight even beats to a bar, played as either a 2-3 or a 3-2 clave. The numbers indicate rhythmic patterns in which notes are alternated in the bars of music. A 2-3 clave, for instance, indicates a bar of music with two notes followed by a bar with three sounded notes. This pattern repeats throughout the song. The clave is the rhythmic backbone of the salsa.
Practice playing walking bass lines with your left hand. A walking bass line is a measure of evenly timed notes played repeatedly, usually forming chord arpeggios (a chord in which the notes are played separately rather than together). The overall sound effect of this type of bass line has a "walking" feel to it, hence the name.
Practice playing fuller chords with your right hand. Salsa uses many standard piano chords such as the G, C, D, and E chords as well as most of the minor chords. What distinguishes the salsa sound, besides its upbeat rhythm, is the voicing of the chords. Rather than play the simple three-note voicing, you should consider doubling the root or playing upper extensions, such as 7th and even 9th chords.
Add melodic musical figures and passing tones into your right-handed chord playing. This means that you will play a rhythm based on a salsa chord progression, then fill in the holes in the music with piano licks (a run of single notes) that use the main melody of the piece and occasionally alter it with a note not found in the chords. This style of playing chords heavily with the right hand while playing walking bass with the left, in conjunction with the rhythmic clave, is what gives salsa its distinct sound.