Watch the More Fills online guitar lesson by Joe Dalton from Acoustic Blues Handbook
These fills give me a chance to teach other things. The first illustrates double stops in the first half, and a short answer to it in the second part of the lick. The second fill illustrates the outlining of the scale with a small tag or period, if you will. Both are familiar sounds. It is also interesting that you should repeat these during the chorus, and they can be used as intros as well.