Watch the She's Leavin' online guitar lesson by David Blacker from Lone Wolf Blues
When I watched Clapton's acoustic version of Love in Vain I knew I had to include a piece like that in this course. This is a bit of a simpler approach to the tune, but it's got all the key elements.
The steady bass rolls throughout the piece and it involves some more complicated right hand movement then in previous pieces as there are some single note triplet lines that happen on the top two strings over the I and V chords.
Over the IV chord you have a great meaty D7 chord with an F# in the bass. Here's another example of using bass notes other than the root note to create some color within the piece. The one real key chord substitution that happens in is in measures 7 and 8 where you have a root (A7) to 5 (E7) change.
This is classic delta blues language and something that you will see more than a few times within this course. The chromatic turnaround in measures 11 and 12 here is another classic delta blues-ism and can be used to begin the tune if you like.
Recommended listening: http://www.youtube.com/watch?v=OZCREueK6OI