for each note do the following

roll the guitar volume down
hammer on the note
roll the guitar volume up after the initial attack
as you lift off the note roll the volume back down so it decays softly and smoothly
rinse and repeat
Actually called Mark!

Quote by TNfootballfan62
People with a duck for their avatar always give good advice.

...it's a seagull

Quote by Dave_Mc
i wanna see a clip of a recto buying some groceries.

Add Delay and basically volume swells and timing takes care of the rest really. I've seen a lot of people wrecking the volume pot of their guitar doing this excessively, but they all had pretty old guitars, I used to play this song quite a bit and never did any damage.