Hi Lisa -Now that's a GREAT photo!!!!!!
I'm just learning tremolo - it is THE sound of the instrument after all I have found a couple of good lessons on Youtube - one of which talked about angling the pick slightly just by rocking your thumb so it glides over the strings and doesn't catch. The other talked about the wrist action, matching your tremolo speed to the speed of the metronome beat, and getting the whole arm totally relaxed so it i just a loose, quick. non stressedwrist action. All seem like good tips. I'm working on double stop temolo too - as I really love that sound and there seems to be a lot of it in the old bluegrass tracks I'm listening to.
Dave - that's lovely playing I've certainly not reached the key of A pentatonic blues page in the book yet!