The secret to building technique is to take it slowly.
Do not speed up until you're playing 100% cleanly at slower tempos. If you force yourself to accelerate before you're ready, you'll be playing sloppy shitty sounding licks at high tempo, which is worthless for any musical application.
If you're stuck at a particular tempo, it's because you're not ready to progress past it. Either your musculature can't handle it, or you're not comfortable with the notes. In either case, if you don't have these fundamentals out of the way, any attempt to speed up will sound like shit.
Not disagreeing with you here, but what would you recommend doing to get past a certain hurdle? Surely there are certain types of practice that will develop desired results for a certain particular hindrance.