A good intro builds excitement and establishes expectations before jumping into a tune…
… while a turnaround (typically the last two bars of a chorus) keeps the musical momentum going and leads the listener back to “the top” of the next chorus.
A commonly-used idea is to emphasize a dominant harmony (the V chord). In this example, a delicious augmented V chord creates an ambiguous harmonic tension that sets up the harmonic release with the arrival of the I chord on the downbeat of the first chorus. Try playing it very freely (not in strict time) in order to heighten the expectation of what is to come…
