When you've been doing it for so long it's like asking someone how you ride a bike.
Okay, here's an 8 bar blues, some of you may recognize this as Eric Claptons (he didn't write it, only covered it) Someday After Awhile
|D7...|....|G7...|G#o7...|
|D7.B7.|E7.A7.|D7.G7.|D7.A7||
most 8 bar blues songs will have a bridge section, in the key of D it would look something like this;
|G7...|....|D7...|....|
|E7...|....|A7...|....||
