One thing you can do is pick the open E slowly at first, make sure your picking is clean and even. The idea here is to pay attention to your picking hand. Gradually you wanna go faster and faster, and then when you're going as fast as you can, keep it at a steady rate until your arm hurts and then slow down. Secondly, rest the pick across your first knuckle on your fretting index finger, and place your thumb across the back of the pick. Choke up on the pick as much as possible, the idea being you want as little of the surface area of the pick going through the string as possible.

Another one is to start at the 15th fret. In between each note you want to pluck three open notes between, and use alternate picking. The pattern goes 15000140001200011000120001100080007000500030002000300000000000
start on the high E and move your way across all the strings.

That's just one of many excercises you can do. The most important thing is, however, to start off slow. I might suggest 80 bpm. Remember if you can't do it fast. you're not gonna be able to do it slowly. ALWAYS use a metronome! This is probably one of the most important things you could do. Try and increase 5 bpms everytime you feel like you've got the previous bpm down pat.

One trick is to increase the metronome way passed the speed you can play. Try and keep up to the best of your ability. Chances are you'll have trouble, but when you got back to the bpm you where working on, it won't seem so hard anymore.

I'm not much of a teacher man but I hope that helps, even a little. Keep it heavy