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…

Watch on YouTube? (Let Frank know if you’d like to see this lesson as a video!)