Pull offs and open chords can cause cool riffs when playing the guitar. Pull Off and open chords also spices up the strumming methods of guitar playing. The picking pattern is also useful in causing great sound with the playing of the guitar. By firmly tapping the chords or hammering can cause a lower sound to the note. Pull offs are effective when used with hammer-ons.
Read the full article here:
Lesson: Using Pull-offs With Open Chords.