Carter-style guitar playing may be primarily based around first-position chord shapes, but within that simple framework there are plenty of ways to make the music come to life.
Example 1 adds an embellishment to a basic G-chord strumming pattern. On beat three of each measure, pluck the open A string and then quickly “hammer” the middle finger of your fretting hand onto the second-fret B note. Do this with the right amount of speed and force, and the B note should sound clearly without any additional help from the picking hand—you’re counting on the leftover string vibration from picking the open A note (along with the impact of the hammer-on) to make the note sound.
In Example 2 the same lick is used on the C chord. Although you’re strumming partial chord shapes on beats two and four of these examples, you should take care to accurately pick the individual notes on beats one and three. In Examples 1 and 2, the embellishments are written as pairs of eighth notes, so you should aim to land the hammer-ons right on the and of beat three, allowing both notes to sound clearly.
Excerpted from Carter-Style Guitar Basics: Carter-Style Embellishments.