guitar hero tips sought

[VanVeen]

i picked the game up last friday and have wasted 15-18 hours since then 5-starring each song on easy and medium (with a few exceptions), most w/98-99% accuracy. i just prematurely moved up to hard and i'm looking for some tips, namely:

i) the tougher medium songs (Institutionalized, Psychobilly Freakout, etc.) and the second tier hard songs (Tier 1 is a joke; Tier 2 seems almost impossible w/my weak skills) all require you do, erm, G-R-Y-B or B-Y-R-G or O-B-Y-R-G sequences very quickly using hammer-ons and pull-offs. i'm having big, big trouble doing this w/the celerity 'hard' requires. what do the veterans recommend? what songs and sections should i practice to improve this skill?;

ii) there are sections, such as the chorus to "Institutionalized" (what a dreadful tune), where you have to do a long sequence of a single fret very rapidly. i presume you have to strum up and down, but how do you keep a rhythm? again, any songs or sections you vets would recommend?

thx in advance. most mesmerizing video game i've ever played. perfect for detilting during my breaks [img]/images/graemlins/smile.gif[/img]