Watch the Classic Texas Blues online guitar lesson by Jeff McErlain from Blues Guitar Survival Guide - Lead
This one is going to hurt, I mean it. These bends are rough on the fingers especially when you first start digging in those strings. There are many concepts at work here, I am bending whole steps, half steps, in between notes, vibrato, and phrasing. But this all really comes down to hand and ear strength. The bends require great control over the string to really get inside the bend, very rarely in this study am I sitting on a non-bent note. That bent note is usually has some vibrato on it and it can be purposely flat to create more tension. This takes a ton of work and compared to Albert I have just scratched the surface. There is no trick to this stuff, it come from listening to the masters, and working on it for years. So what we hear when we listen to these guys is talent of course, but more so experience.