Many people start of wrong, by holding the pick in an ineffective manner. EddyGaz explains how he holds it and explains what position your hand should be in compared to the bridge and the strings.
Sweeping is some of the hardest stuff you will ever do on a guitar. EddyGaz makes it look really easy only after a little practice. It should give you some motivation to try it out yourself.
This is a great series of videos that will help you out while learning to shred.