Just doing things really fast
I've hardly done any separate technical exercises, except learning the major scale and some chromatic Hammer-Ons and Pull-Offs which I still need to work on. What I think is most important is that you practice what you need to learn, or know is wrong, with concentration!
Whether I'm learning songs or playing them, I am very analytical of my playing. This means I'm thinking about my problems and I can then move past them in due course. I could do boring technical exercises all day and try to force myself to concentrate, but I guarantee I couldn't keep the mind focussed enough.
Basically what I guess I'm saying is the more you practice with your mind focussed, the faster you'll progress. I'll agree that its better to play what you want to play and progress to that schedule instead of a mindset of 'I want to play faster because thats better'.