hey,
I haven't been playin real long, but palm mute is simple, just put your pickin hand over the strings, and u can like rest hard to get a real dead sound and as you get to playin slightly lift off to give it a fading in sort of sound and stuff like that. Muting is really useful, and if you've got like blank spots that need a fill-in or somethin, just mute your power chord between your newxt one and it makes a good sound, like with last resort by papa roach, I mute it between the strum to give it somethin extra

e-------------------
B-------------------
G-------------------
D-------------------
A-99--77--55--4--7--
E-77--55--33--2--5--

is how it is supposed to go, but instead i play

mmmmm mmmmm mmmmm
e----------------------------------
B----------------------------------
G----------------------------------
D----------------------------------
A-9999999--7777777--5555555--4--7--
E-7777777--5555555--3333333--2--5--

just mess around and enjoy it