Watch the Broken Chords online guitar lesson by Matthieu Brandt from Jump Blues

Another cool way of accompanying is to not play the chord in a strumming pattern, but to play all the notes separately.
The trick is to play them in a way that once you've played a note, you let it ring out as long as possible. By playing very accurately and avoiding touching the strings that already sound, you're outlining the chords.
The rhythm pattern you choose has to be constant, to not be mistaken for an attempt to solo.