A good way to progress would be to learn to play the minor pentatonic scale in any key, anywhere on the fretboard. For a long time I was stuck with playing in 1 or 2 positions, which limits your playing alot.
I have an excellent book which helped me progress alot with my soloing, the book is:
Fretboard Logic SE
http://www.amazon.com/exec/obidos/tg/detail/-/0962477060/qid=1080521212/sr=8-1/ref=pd_ka_1/104-3312649-0485534?v=glance&s=books&n=507846Nice and cheap, and definately one of the best guides to scales and other aspects of guitar playing i've seen. It mainly deals with the CAGED system, but makes it very clear.
Another few things things to practice would be to be aware of what notes your landing on when soloing in a particular key, for instance landing on the root of the chord your soloing on doesn't always get you the best result, likewise playing the scale of the chord your soloing over isn't nessecary, there are other alternatives. Also, concentrate on what your going to play before you actually play it, don't blindly moved around the scale. If your stuck in the habbit of starting your scale on a certain string, try starting on a different octave, or start on the 3rd or 5th of a particular scale, just try different things out.
Those are just a few tips anyways, theres tons more you could do. Just that alone could keep you going for a long time anyway.
Hope that helped.
- J