Watch the Power Chords online guitar lesson by Angus Clark from Hard Rock Survival Guide: Rhythm
In designing this course I've intentionally gone from full chords and basic rhythm strumming, to partial chords and more precise right hand movements. So the first partial chord we are going to look at is the power chord, or 5th. A chord with no third in the root position.
First off - make sure you only hit the strings you want to have ringing. When you're playing big chords it's easy to mute a certain string with a finger on your left hand and play through it because you're making such a big noise that the sound of the one dampened string gets buried by the sound of the ringing strings. When you are playing a power chord, any other string getting hit will create a noticeable sound, and it should be your choice whether to include it or not, not simply a limitation of your technique. When you're playing a rhythm part in power chords, there is a lot of finger sliding that happens and the number one thing you want to look out for is how to minimize the noise of your fingers sliding on the strings. So we're going to isolate the various chord motions into horizontal, vertical, and then the combination of the two. You'll see how I use fingering options and targeting to help alleviate the amount of finger sliding that I actually do. It's inevitable that you'll get some noise - but be aware and keep it in mind throughout the course.