A lot of this rhythm picks the root note (muted and trem. picked), and then power chords are played, without the mute. All it really takes is practice, picking a ton in between where you play your chords. I'll try to put up a lesson some time, but what the others said is true, just copy other songs. Its probably the best way to figure it out.
There are only two important things in life - There's music and theres girls, not necessarily in that order....
The Ace's Guitar Tricks