
I'm not sure there are many guitar techniques that are purely used by blues guitarists but there is no doubt that string bending, sliding and vibrato are very strong techniques used in blues guitar playing. A lot of the techniques discussed here are used mostly with lead guitar playing. Once you can play the common chords and scales used in blues, you will be ready to get to work on your technique. Good guitar technique and articulation is far more important than how many notes you can play in a second, especially when it comes to blues guitar.
This section isn't going to be a lesson in guitar techniques, more a discussion about the types of techniques you should be learning. The most useful of them would be vibrato, bending, hammer ons and pull offs, sliding and muting /damping. These guitar techniques ultimately add to the sound of blues guitar.
Most of these techniques are quite easy. The two that take more practice are string bending and vibrato. A good blues solo relies more on good technique than it does on knowing all the scales and fast runs. Phrasing really is everything in lead guitar. A good guitarists with excellent command of these techniques can do a lot more with only a handful of notes than somebody who can play all the scales at lightning speed with little else happening. Sure, speed can be impressive but without good technique you won't be impressing people for very long.
It's important to spend more time practicing good technique and let the other stuff come later. Unfortunately a lot of beginners tend to spend more time trying to play fast blues runs and scales. Like it or not, this will result in blues solos that are far less interesting while taking longer to master than getting the techniques down first. There are plenty of good books and tutorials available that show you how to master these skills. String bending is one of the things that stand out the most with amateurs. Make sure you are recording and listening to your practice when you learn to bend strings. Once you can bend a string to pitch correctly and make good use of your vibrato, you will be miles ahead of the rest of the crowd with only a few notes!