#1
I've noticed a lot of rock/metal uses artificial harmonics, whether it be in a fill or a solo. I've always wanted to learn how to make my strings squeal like that. I recall watching a vid of Satch teaching artificial harmonics on youtube, but I can't seem to get it right.

IIRC, you lightly brush your thumb across the string with your pick stroke to create a harmonic...if that's correct then I must be doing something wrong because the sound I get is either a light muting of the note or a dead note all together.
Setup:
Ibanez GRG170DX
- D'Addario 9s
Squier Stratocaster
- D'Addario 11s
Kona Cutaway Acoustic
- D'Addario 12s
Kona K35 Amp
Rocktron Metal Planet Distortion Pedal
Dunlop Original Crybaby Wah
#2
Its quite a hard thing to get... But yes you do brush the string with your thumb... But its very very light and only for an instant... Basically your just touchin the string to put it into a different vibration pattern (figure 8 if im not mistaken)

So just quickly lightly tap it..... Do not remain on for more than a split second...

The way I learned was to simply pick the string and let it ring... Then lightly touch it with my thumb (well after the initial picking) to get the sound... I kept doing that for ages till I was comfortable with the amount of touching required... I then tried to implement that at the same time..

It does take a bit of work.

Use lots of distortion as well as it makes it easier at first and therefore a good way to learn.