The two things I found the be hardest were moving your fretting fingers at the same speed as the pick and muting the strings you weren't picking. To solve the timing of the picking with the fretting just take it as slow as you can. Sweep slower than a sloth moves if you can. That also directly relates to muting. The thing about muting is it pretty much requires both hands. Have your picking hand slightly dampening the strings so they'll hush up with minor noise. On your fretting hand. When you make it to the second note of the sweep make sure the finger that was fretting the previous string is no longer fretting it. At least that's the best I can describe it. Anyone else feel free to elaborate off this.