Adam Gussow has a few videos on comping, including this one:
My 2 cents: I don't think Johnny Woods is comping in the clip above. I guess he is accompanying his own voice, but that's not how I understand comping.
I think this early recording with Little Walter is a great example of comping. Pay attention to the harmonica's interaction with the vocals and the guitar. To me, that's the essence of comping.
If you want to hear more expert comping, just listen to any Muddy Waters recording with Little Walter. Definitely check out "Long Distance Call" and "Baby Please Don't Go" off of Muddy Waters - His Best, 1947 to 1955. (If you play blues you must already know Muddy's music, right?)
Comping is accompanying, i.e. not soloing, but adding to the mix without stomping on the singer or other soloist. IMO, you can't get a better example of good comping than Kim Wilson's work on Jimmy Rogers' last album, "Blues, Blues Blues" (as well as generally great playing and singing by Jimmy, his band, and the "all stars"). ----------
