Another popular sound is the use of hammer-ons with 7th chords. It is particularly common in Southern R+B styles often referred to as Swamp Music. Here is the basic sound. Practice it slowly at first to be sure all the notes are sounding clearly.
Here is the basic pattern again, this time with single note riffs added to it.
The following solo uses a new technique – the trill, which is a rapid succession of hammerons and pull-offs, with only the first note being picked. The trill is indicated by the symbol J above or below the two notes concerned