Watch the Chord Changes online guitar lesson by Brad Carlton from Guitar Lab: Solid Strumming
This lesson presents a number of techniques to enable you to change chords quickly and efficiently while preserving a legato sound. Pivot fingers are defined as: same finger, same string, same fret. Guide fingers are defined as: same finger, same string, different fret. Remember guide rhymes with slide. These are two of the most important techniques in establishing fingerings which are efficient.
One of the most common errors in guitar rhythm is what I term the "ah" of guitar playing. It would be like me trying to tell you something and saying "ah" every other word. This frequently occurs on the last upstroke right before a chord change. In the video I will demonstrate how to delete this upstroke to provide time for you to efficiently change chords. As long as you stay in the pocket rhythmically, you won't even notice that you didn't play on the last eighth note.
There is an illusion that can be created by utilizing open strings whenever you change chords. I demonstrate this in the video. Make sure you include this technique in your toolbox because it can make the difference between a smooth flowing lyrical performance or a choppy unmusical performance.
I reference diatonic harmony as a way to group chords together.