Watch the Arpeggiating Chords online guitar lesson by Tony McManus from The Celtic Journeyman
When I invented that mundane little arrangement a few minutes ago what I was illustrating is the idea of carrying a melody on the top two strings maybe. There’s a bass line on the bottom string and you have a whole series of strings in between so what I tend to do is arpeggiate the chords and the idea is to fill out the arrangement. We are trying to orchestrate a relatively simple melody with one instrument. One approach is to have arpeggios between the bass line and the melody.
You need to be aware of not confusing the listener. They have to know that that is the melody note, that is the bass line and, in between, be aware of the dynamics. Using this technique you don’t want to have everything at the same level. It’s not a harpsichord- there are dynamics involved. You don’t want arpeggios to fill out to the extent that it crowds out the melody.