Fast picking is as much, or more dependant on your fretting hand. Try practicing your riffs, or solos, or whatever your needing speed with without using the picking hand so much, you know, not so many strokes! Most of the really sick shreeders are getting their sound mainly from the fretting hand, of coarse picking too, but with more finess than just grinding out 3000 rpm up stroke/down strokes mindlessly. Start workin those speed riffs , and fancy fingering with some, hammer ons, and pull offs(fret hand), and give your pick a break! but thats just me.