Watch the Fareed's Trade Secret #3 online guitar lesson by Fareed Haque from Jazz Comping Survival Guide
This is a sweet way to create the illusion of complex moving lines (Guitar playing is almost always about creating an illusion - the illusion of the miniature orchestra, of the walking bass line. Playing guitar is always a bit of a slight-of-hand magic trick.) is to simply move one voice under the melody, or moving one voice while holding the others. This is called using 'oblique motion'. You can also try using 'contrary motion' - two voices moving in opposite directions - by playing say a G7b5#9 (guide tones plus 2 extentions) and bringing each note on the 'E' string down by 1/2 step while bringing each note on 'B' string up by 1/2 step. The lines move in opposite directions. Often just holding a chord and moving one voice by 1/2 step will make your chords shimmer and glimmer. It creates the illusion that more is going on than actually is. Sneaky!