Interesting mix of cards. I like the theme you're going with. I'm not terribly good at deck construction, but here are some of my thoughts:
The
Vampire Nighthawks for example are rather quite amazing. Get rid of the 2
Markov Patrician and put in more Nighthawks. They both costs three mana, but the nighthawks will last longer and are more of a threat with their death touch.
Gatekeeper of Malakir are useful too.
Malakir Bloodwitch and
Anowon, the Blood Sage would bet better choices for your high mana cost spots. The
Bloodline Keeper from the latest expansion would work nicely too.
Look into
Urge to Feed instead of
Dead Weight. It can still kill something small, and can make your creatures bigger. However, as
Dismember would work better, but they're most expensive to buy.
Might want to add another couple of lands. See how it plays out though, might not be a problem, most of your cards have low mana costs.
You've only got 10 red cards, I'd almost consider taking them all out and sticking only to black cards.
Into the Maw of Hell and
Night Reveleres are rather expensive for what they do. Better to find another more useful vampire, and add another cheap kill card. A
Go for the Throat or two perhaps.
As a fairly new player, I imagine you just play with your friends? Card legality isn't a big deal if you're just playing for fun. I've been playing on and off for nearly 10 years now, and most of my decks aren't legal in any tournament format. They don't always win, but they're still fun to play with.