My advice is to not hold on to the pick. Some videos of advanced players may look like they are holding it, but they are actually not. It's very hard to be accurate when you hold the pick, and also very tiring. Ideally, songs like Dragon Blade, (not the fast shred in the middle), should be alternate picked for the entire song. What I do is put my thumb above the pick, and curl my index underneath the bottom. I then mostly move my wrist up and down, I hardly move my arm at all. This helps to conserve stamina and improve accuracy. Some people use their middle finger instead of their index for the uppicking, it's all personal preference. Start slow, even on a song that you can downpick comfortably for the whole thing. Maybe something like Honjitsu wa Seiten Nari or Tsubasa would be good. Even when you miss a lot of notes, just practice doing alternate for the entire song, you will get it in no time.
