Watch the Bends & Vibrato Exercise 1 online guitar lesson by Jeff McErlain from Beginner Blues-Rock Soloing
For the love of all things, please, please, play in tune! I could not be more serious about this. When I hear a guitar player, and believe me there are many of them, playing out of tune, I immediately lose interest. I do not mean out of tune as in his guitar is out of tune, I'm referring to out of tune bends and vibrato. I have found this technique to be one of the main things I discuss with all of my students.
I clearly remember a time in my own playing at college where my roommate called me out on this. He was right, and I'm eternally grateful to him. He flat out said, "Dude, your bends and vibrato stink." At the time I wasn't so happy to hear that, but he was absolutely right and it changed my playing.