I know this all has to do with pick angle, but I keep falling into that bad angle when playing anything fast, and I get the little scraping sound instead of a clean attack. One thing that helps me is to hold the pick at the side instead of the normal way, so I'm picking with one of the top edges instead of the 'tip'
Anything I'm not thinking of here?
1) Paul Gilbert actually encourages that soubd.
2.) Google Troy Grady's documentary. Tons of insight onto picking.