One of the most important principles behind compelling music is the balance of tension and release. Tension is what drives music forward, creating a meaningful narrative. Having an awareness of current chord tones is necessary for you to be able to create or resolve tension with intention.

A common melodic device which incorporates this balance is suspension. In a suspension, a note of the previous chord is sustained in the melody, creating a moment of dissonance before resolving to a note of the new chord. Anytime a less stable note is emphasized against the current harmony, this creates tension, setting up an expectation for resolution and pulling the melody forward.