Heavy strings give you better tone. I use D'Addario EXL115's (.011-.049) on all my electrics. SRV used GHS Boomers in .012-.054. I think you'll agree he did some fairly energetic bending and vibrato.

Don't be afraid to use several fingers on one string to make a bend. You will often see what looks like a two-semitone bend done with only the pinky finger, but close inspection will reveal that two or three other fingers are helping out, while also muting other strings.

Vibrato comes from rolling your fingertip back and forth between the frets. You should exagerate the movement at first, to get a 'feel' for it. Try to get the effect of the ringing, stinging notes that BB King uses in his solos. From there, it becomes easy to back off to a more subtle effect.

Like any guitar technique, it comes down to practice. Get it right at a slow tempo, then gradually increase your speed. In time, it will be as natural to you as breathing.