Power Chord Shifts & Palm Mutes
You have the basics down, but if you really wanna rock then you have to master another couple of tricks...
Shifting Power Chords with a little lift
Moving power chords around should be easy, and it is if you use this little trick. What you want to do is keep the fingers in contact with the strings all the time when you change chord. Don't lift all your fingers off and replace them each time, because it's far too much wasted effort. The chord grip stays the same all the time, so it should be easy, right?
So what I recommend you try is moving your power chord grip from, say, a G up to a B (6th string root) and try and make sure that your hand shape stays the same, and that the fingers never leave the strings. However, don't keep pressing hard or you will hear a really strange sound while you slide the chord up. The trick is to play the first chord, and then when it's time to shift the chord you relax your fingers while keeping them in the right place. Leave them lightly touching the strings and then shift to the place for the new chord, press hard again and then play.
If you press too hard you will find that the friction of the strings will move your fingers out of the correct chord form, and if you press too lightly or remove your fingers you will get open string noise (and when using distortion the noise becomes significantly greater).
This is easier said than done, but it shouldn't take you much practice, and it will really improve the sound of your power chord songs!
The outside of your picking hand palm will rest on the edge of the bridge and lightly mute the strings so they sound a little dead. Makes it more of a ‘chug' sound than a ‘ringing out' sound, that sounds especially good with a distorted tone.
You have to experiment with exactly where to put your palm down, that is, how far away from the bridge to rest it. If you're sat exactly on the bridge, then the effect will not be noticeable, but if you're too far towards the neck, the strings will be so dead you won't hear any note at all, just a click!
In practice you'll choose different positions depending on what you are playing, the song, the style, and your mood.
From one extreme to the other - time for some fingerstyle!