Watch the Level 3: Blues Bends online guitar lesson by Jeff McErlain from Take 5: Blues Bends
I'll take this space to discuss the importance of bends and vibrato. I've said it before and will say it again, these two techniques help define the player, vibrato in particular. The technique is essentially the same for both bends and vibrato, but you have to work on each one specifically with intent. I still work on them all the time, and I find when there are periods where I don't get much time to practice or play, the bends are one of the first things I feel suffer. It's always about hand strength and control.