To practice vibrato and bends simply keep doing them. The best way I find to practice bends, and the most fun IMO, is to hit a note on the low E string, then take a note high up on the neck and bend it up a full step to the note I hit on the low E. For instance, hitting the open E string, then bending the 15th fret on the second string up a full step so it matches the low E. When you do this, don't let the low notes ring out when you play the high notes, it just sounds messy, simply mute the string with your palm when you go to pluck the 15th fret. Also, adding vibrato on top of this makes it so much sweeter. Use the open E as a guide, if your not matching it with the bent 15, then your not bending enough or your bending too much.
So give that a go and try it with different notes, though you might have to do a small slide into the higher frets to make a good transition.
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