Watch the Slow Fuse online guitar lesson by David Hamburger from Essentials: Fingerstyle Blues
There are two more great things about playing in this kind of call-and-response vein. One is that it serves as a kind of automatic taste enforcer: if you’re spending half your time laying down the vamp figure, you’re never going to find yourself overplaying in the licks department. It’s hard to go on too long when you only have a measure or two at time in which to improvise. The other benefit, particularly if you’re relatively new to improvising, is that it sets up some pretty finite spaces in which to do that improvising. I like to think of it as taking a wide-open field, where you could run anywhere, and setting up a relatively narrow set of cones to thread your way through.