Here is a terrific little guitar exercise that gets you playing fourths with the 1st, 3rd and 4th fingers while improving adjacent string picking technique. Follow the positions and indicated fingerings. The bar line placement that I have chosen sets up some nice syncopations that the student can explore at various tempos, but try other accents too. Once the fingering begins to feel more natural it’s a good idea to begin applying various rhythm figures to the line. In the improvisational context, try these ideas over various altered harmonies.  

This exercise is dedicated to Jerry Lavene, a former instructor of mine, who first showed me the descending part of this line several years ago.

The image below while lacking the charm of the handwritten notation is at least a little easier on the eyes.