Learn to play 'Can't You Hear Me Knocking' by The Rolling Stones. This tutorial is in open G, the tuning that gives The Rolling Stones their signature sound.
Mostly based on double stops, this riff doesn't move around the neck too much but accuracy of the notes is quite important when barring across two strings! After that, it's just piecing together the sections as they have slight variations each time.
Open G tuning - xGDGBD
In open G tuning, your low E string is tuned down a full step to a low D, or in the case of Keith Richards - removed completely!
Your next highest string, A, will drop down a full step to G. Your D, G, and B strings will stay the same, while your high E string is lowered a full pitch to D.