Watch the Repeat That online guitar lesson by Jeff McErlain from Solo Factory: Chicago Blues
Here is a nice IV7 - I7 lick that starts off with the repeated motif. Repeated licks are exceptionally important and very common in guitar. I find listeners really react well to them as they often build excitement, and give the ear a bit of a break. I highly recommend building up your arsenal of repeated licks. I am using an A Dorian scale on this particular lick on the IV7. To return to the I7 (A7) chord I add in the natural third (C#). This outlining of the chords is a great way to add some hipper sounds to your playing.