The Legacy forum is mostly for tournament preparation and discussion for the Legacy format. While your deck is Legacy legal, I'd say the Casual forum would probably have more helpful suggestions for your deck. Just because it's the wrong forum doesn't mean I can't help though.
I'd say start with more 4-of's, if possible. Find the best cards in your deck, that you want to draw the most often, and try to get 4 of them. These are probably Gatekeeper of Malakir, Captivating Vampire, Pulse Tracker, Sangromancer, and Feast of Blood. Also, try to get a playset of
Vampire Nighthawk 
it is, arguably, the best vampire ever printed.
Creatures over 4 mana should be 1-2 of's, each, if they're good. If you find yourself never casting them, or casting them and not winning the game, try to swap them out for other big winners. Try
Vampire Nocturnus 
if you can get ahold of one. Hope that helps!
Hey diddle diddle, the cat and the fiddle, the cow jumped over the moon.
The little dog laughed to see such sport,
And the Dish ran away with the Spoon.
He ran from conviction, and fed his addiction as the Dish heated the Spoon...
The Spoon begged to go, but the Dish shouted : "NO!!"
"The heroin will be ready soon!"
"Any time doing the right thing is funny as hell, it's probably Chaotic Good."
