To do a run on a chord is very simple. It adds a rather unique beat to a song. Run on chords are great when you are accompanied by a piano or even just a solo. All you are doing is hitting a series of three notes in between chord changes. Before switching chords, play the notes and as soon as you hit the last note switch to the chord that you desire to play after that. Here is an example:

Going from a D to a G:

e|-----------|
B|-----------|
D|-----------|
G|-----------|
A|--2--0-----|
E|--------3--|

So you would play the D chord then before switching to a G chord play the notes above.

Going from a G to a D:

e|-----------|
B|-----------|
G|-----0--2--|
D|--2--------|
A|-----------|
E|-----------|

So you would play a G chord then before switching back to an D chord play the above notes.

Going form a D to an A:

e|----------|
B|----------|
G|----------|
D|-----0--2-|
B|--2-------|
E|----------|

So you play the D chord again and before switching to the A chord play the above notes.

Going fom an A to a D:

e|-----------|
A|-----------|
G|-----0--2--|
D|--2--------|
A|-----------|
E|-----------|

So you will play the A chord and before switching to a D chord play the above notes.

Note: Play the notes as you see them. It is just like reading a tab. you can expiriment with any chords. I find it easier to play in D,G,and A. You can also expiriment with any tune. These go great with country and gospel music.