Glissando or slide guitar technique sounds really cool on power chords.
And also often used on single notes in guitar soloing. For example Steve Vai and Joe Satriani extensively use glissando in almost every solo.
Slide technique helps creating personality and articulation to playing, as well as adding accents on notes which need to stay out of the rest.
In order to perform slide, play any note, and then glide the fretting finger to another fret, the note at that fret should also sound (this time without picking the string with plectrum), watch my video below.
Here's a few exercises to help you work out the slide technique. After you manage them, scroll down and enjoy impressive Heavy Metal riffs.
Play this exercise using for slide just one of the fingers on your fretting hand at a time, begin with the 1st, later switch to 2nd, 3rd and 4th finger.
watch the video
in ASCII guitar tabs, slide towards the guitar bridge (upwards) indicates by slash symbol "/", and towards the guitar head by backslash "". Also slides can be notated with "s" character.
In order to get the tasty vibrato on the last note of this lick, lift and descend or move in circular motions the fretting hand around the fret while the string remains pressed down.
The last slide of the lick, doesn't have specific destination, just slide somewhere on the fingerboard and release the hand, this type of sliding technique is called "slide out of a note".
Now let's slide power chords, all the principles of gliding remain the same...
A slightly different approach to perform slide guitar technique, is instead of making destination note sound purely by means of inertia from the previous one, play the source note, and when you'll need to slide, immediately pick the string(s) again. This extra punch will make the slide effect more noticeable and pump more, volume to the destination note.
Note that in many guitar tabs legato notation is added in the way of slide notes, but only if a subsequent note generates sound from gliding.
Click here to open free video guitar lesson "Playing Rhythm Like The Masters" from GuitarTricks.com. In this video you'll learn how to play guitar riff in a style similar to James Hetfield of Metallica using palm mute and some slide technique.