Watch the Fareed's Trade Secret #9 online guitar lesson by Fareed Haque from Jazz Comping Survival Guide
This is sort of tricky for the left hand, but with a little practice it goes a long long way. Up to now we've played guide tones with other notes simultaneously. Now try playing a melody note first, holding it and playing theguide tones after and under it. For example, play a G on high 'E' string with your first finger, and while holding it play guide tones of G7 w/ your 2nd and 3rd fingers. If you play long melody notes and short 'stabs' with guide tones it creates the illusion of a soloist and accompanist. Pretty cool. Check out Jimmy Wyble. He is a master of this approach.