The first thing I should mention is that a lot of your spells and creatures are underwhelming, and the ones that are good really should go up to 4 copies (usually). Also, your sideboard makes very little sense, and looks more like a collection of cards that didn't make it into your maindeck opposed to specific answers for troublesome decks in your meta. Here's a revised list, and I must warn you, I am going to do some aggressive chopping, and am not going to be keeping a specific budget in mind.
4 Stromkirk Noble
- Arguably the best 1 drop creature in standard. You want 4
4 Bloodline Keeper
- A compete house, even if he doesn't flip.
4 Adaptive Automaton
- Gives all your dudes +1/+1. I like him over Rakish Heir since he doesn't require your guys to get a hit in before the bonus takes effect.
4 Vampire Interloper
- Probably the default 2 drop creature for black/red. 2 power and flying work in the deck.
2 Olivia Voldaren
- This card is insane. Don't let anybody tell you otherwise. If she stays on the table she wins games.
3 Rakish Heir
- Good, but not great, since you have to actually connect with your creatures before they get a bonus. I was hovering between a 4:2 split of this and Bloodcrazed Neonate, and just decided to go 3:3
3 Bloodcrazed Neonate
- A decent 2 drop. Not exciting, but decent.
4 Brimestone Volley
- A great burn spell. The fact that it can potentially do 5 to somebody from nowhere is amazing.
4 Doom Blade
- Probably the best spot removal for your deck, since there is very little black running around these days
or Gut Shot
- There's enough 1 toughness that both are relevant. Geistflame provides card advantage, but gutshot can cost 0. I personally prefer Geistflame, but it's your call.
4 Dragonskull Summit
- A strict improvement over a basic if you can afford it.
4 Blackcleave Cliffs
- See above
3 Stensia Bloodhall
- It gives you reach in the late game, helping push through those last few points of damage.
s - You have a slight bias towards red in the deck, as reflected in the additional mountain.
3 Arc Trail
4 Tribute to Hunger
3 Sever the Bloodline
3 Curse of Death's Hold
2 Witchbane Orb
Now to explain what I did.
The first thing I did was go through your list and cut the cards I don't like (mainly because they aren't that good, but also because of other factors, such as not working in the direction of your deck)
Vicitim of Night: I cut this because of the double-mana cost. The increased difficulty in casting this in your deck doesn't offset the increase in power, so I replaced it with Doom Blade (which is a better choice over Go for the Throat because there are so few black decks in the current meta).
Tribute to Hunger: In a slower deck I'd play them in the main, in yours they're better in the side against decks with a lot of hexproof creatures or only a few large threats.
Maw of the Mire: Generally speaking, targeted land destruction is bad, and this is no exception. By the time you cast this they usually won't care about a land, so really all you are doing is paying 5 to gain 1 life, which is not good.
Curse of Death's Hold: Sideboard material against aggro deck and MAYBE against Inkmoth decks, not maindeckable.
Traitorous Blood: Usually you'd rather just have another creature or removal spell, so I cut it.
Vampiric Fury: The effect just isn't worth a card in standard.
Curse of Stalked Prey: Some people like this. I don't, mainly because it is so easy for this to just sit on the table doing nothing. Having another creature or spell is probably better.
Blood Seeker: Maybe sideboardable against tokens, but in the main deck this doesn't do much against most decks.
Falkenrath Noble: Same as Blood Seeker
Stromkirk Patrol: Too expensive for what you get.
Manor Skeleton: Too small, and not a very good creature. There are better choices.
Balefire Dragon: Far to expensive for this deck. Olivia Voldaren already tops out your curve.
Instigator Gang: I've found that they don't flip enough to be relevant. Although it is an interesting card, I personally think replacing it with something smaller and faster would be better.
Dragons Claw: As a general rule, life gain is bad unless it comes attached to something that's good. A do-nothing artifact is not good.
Trepanation Blade: This is just a bad card. The variance is too high and for every time you flip 10 cards you are going to have 40 times where you flip a land.
Hope this helps