The single most important aspect of all slide guitar playing is the ability with the right hand to block and damp successfully to cut out the unwanted notes and noises.
Of course, the first thing to keep in mind is that slide guitar is like playing another instrument; it’s not just guitar with a slide on your finger. It must be fingerpicked, and the right hand must also do the complex job of blocking and damping out of all those unwanted notes, especially as the lick is moving from one string to another.
The basic rule is that as the lick moves towards you, the very fingers that plucked the strings then serve to eliminate them … usually just as a new string is sounded, thereby keeping a smooth slide sound connected from one note to another. We then move the fingers in a group of three … so if, for example we were playing the top three strings, and then introduced the D string, those three fingers would now move in a group to cover the D, G and B strings.
Simultaneously, the thumb – which is resting on the lower strings, and also acts to dampen out the lower strings – allows the new string to be introduced. It also acts as the dampening tool if the lick moves towards the high E string, as well.
The lesson itself will obviously explain a lot more of what I mean, in an easier way to see, so I hope you enjoy it. It’s very crucial to all slide guitar playing!—Arlen Roth