Well, you didn't mention your level or anything like that, but here's a specific technique that I'll mention. Forgive me if this is something you already know.
You hear a lot of blues players play nothing but the minor pentatonic or the blues scale throughout an entire solo. And while this can certainly be made to sound good, you'll open up your options for sounds quite a bit if you start thinking about combining the major pentatonic, blues scale, and minor pentatonic at the same time.
For instance, if you're playing over a C blues, instead of just playing a typcial guitar minor pentatonic lick like this maybe:
p
--11---8---------------------------------------------------
-----------11---8------------------------------------------
p
---------------------10---8--------------------------------
-------------------------------10---8----10----------------
------------------------------------------------------------
------------------------------------------------------------
You can maybe start off with C major pentatonic, then move into C blues, and end back with C major pentatonic. Something like this:
C maj. pent. C blues scale C maj. pent.
-----8------------------------------------------------------
p
---------10---8-----------------------------8----------------
s p h
-------------------11---10---8--------------8-9--------------
p
----------------------------------10---8--------------------
-------------------------------------------------------------
-------------------------------------------------------------
p = pull off, s = slide, h = hammer on
(Hope you can read this! I'm not used to writing out tab on the computer like this!)
This is a very simple technique that'll give your sound much more variety. You'll find that it works better at times than others. For example, if you're playing over a blues in C, you probably won't want to use the C major pentatonic over the IV chord, F7, because F7 contains Eb. So the C minor pentatonic/blues would sound better there. Or the F major pentatonic or F Mixolydian mode would be a good choice too.
There are lots of different scale choices obviously, but this scale combining technique is, for some reason, something you don't here a
lot of people do. A lot of players know both scales (or all 3 if you count the blues scale), but they'll only play with one of them throughout the entire solo. It's more rare to hear players combine the scales all in one phrase.
There are lots of good examples of players that do this regularly (Larry Carlton and Robben Ford, both mentioned above, do this all the time), but a really good specific solo is SRV's "Lenny." He does a great job mixing major and minor pentatonic sounds throughout. Check it out!
Anyway, there are lots more ways to add variety to your blues solos, and this is just the tip of the iceberg. But it's a simple thing that's within most people's immediate grasp, and for some reason most people just don't think about it.
Hope this helps! Good luck!
