Watch the Intervals 2 online guitar lesson by Matthieu Brandt from Jump Blues
Using a major or minor third interval in your accompaniment is a great way to thicken it up, without being in the soloists face or irritating the singer.
Play clear patterns in your riffs that are repeated, so that the audience knows that this is an accompaniment, not a solo.
Major and minor third intervals can be found easily on two adjacent strings.
Find the tonic and the third is never far away.
Remember to move with the chords, because all these intervals come from the mixolydian scale of the chord you are on.