Strumming’s great, and once you can move smoothly from chord to chord there are a million songs you can play with that wide-open, down-and-up kind of strumming. But chances are you’ve run across songs that don’t sound quite right when you just strum the open chords. If you want to put a little more of a percussive groove into your playing, you may want to check out the sound of fretting-hand muting. The name explains what it’s all about: muting the strings with your fretting hand. But the question is, how?
Let’s start with Example 1—a basic down-and-up strum on an open D-major chord. Let your fretting-hand thumb drift up over the top of the neck to mute the low E string so you can just wail away on the remaining five strings.
Your pinky should still be free if you’re fingering the D chord with your index, middle, and ring fingers. Lay your pinky down across all six strings (if you can—if not, the top five strings will do as long as you’re still muting the low string with your fretting-hand thumb). Just rest your pinky on the strings without pressing down at all. Don’t fret anything with your pinky; just mute the strings.
Now strum the D chord like you did before. Example 2 shows what this looks like in tab and notation. You should just hear the sound of the pick scratching all six strings with no chord sounding.
Excerpted from Rhythm Guitar Essentials