#2
I think a lot of people just noodle around with individual notes, and then you just add the fifth's to make the powerchord using the original note as the bass note. Thats basically it, unless you want to get into chord theory and progressions.
#3
listen to the beginning of bad seed by life of agony its actually pretty easy
Have:
Dean DOF w/ Seymour Duncan Hot Rodded Pickup Set
Mesa Boogie Rect-O-Verb 50w Head
Randall KH-120 Cabinet

Want:
Marshall 1960a Cabinet