Hi my name is Jose Luis and Im from Peru (btw, if you have read my friend's emails you might wonder why you get so many different names from the same account. Its because our english is not so happy so the one guy with a dictionary has to translate it for us). Right now I play a grave-pact based deck with some zombie/undead theme going on thats quite nice on clearing the board but seems to have an acceleration problem. It goes great IF I draw the right thing on the right time, else I end up topdecking and praying to the heart of the cards >_<.
 

Our set-up is pretty casual, although for some reason we are force by the evil gnome Paul to play standard-legal cards only. Anyways, here goes the decklist:

All creatures ever do is die anyways deck :D

Lands: 21

Orzhov Basilica x4
Godless Shrine x4
Swamps x8
Plains x5
 

Creatures: 25

Festering Gobling x4
Nantuko Husk x4
Gristle Grinner x4
Teysa, Orzhov Scion x3
Endrek Sahr, Master Breeder x3
Helldozer x4
Bellfry Spirit x3

Other Spells: 14
Grave Pact x3
Mortify x4
Debtor´s Knell x3
Orzhov Signet x4

Sidedeck:
Return to Dust x4
Proper Burial x4
Gleancrawler x3
Phyrexian Arena x4
 

Thank you in advance for your time.

That should help you get the colors of mana you need more easily, but getting land is one half of the equation.  The other half is having spells to play.  To wit-- what is Helldozer doing in here?  This is just plain bad-- a 6/5 for 3BBB with no trample or evasion, that has an expensive ability which taps it so you can't attack!  Yes, yes, it untaps if you target a nonbasic land, but by turn seven, why are you worried about spending BBB to destroy a nonbasic land?  They should have all the mana they need at that point anyway.  Take out Helldozer.  In its place, you should add something that will be easy on your mana base.  A really good choice would probably be Gift of Estates, since it can go get you three Plains (or Godless Shrines) and thus take land out of your deck, so you're more likely to draw a spell when you need one.  You did mention your difficulties topdecking.  But between Flagstones and Estates, this deck just doesn't have all that many Plains to search for.  If you can't get Flagstones, Estates would make a good card here, but otherwise I'd prefer you found a creature to fill this slot, to ensure you'll have sacrifice fodder if you need it.  Orzhov Guildmage would be a nice inclusion who can gain you life, and his black ability has a lot of impact in multiplayer.  Mourning Thrull has the same hybrid benefit going for it, can also help you gain life, and has flying if you need such a blocker.  Both the Thrull and the Guildmage are also both black and white, so they interact with Teysa well.  And because their mana costs are fairly low, it's unlikely that either will trigger Endrek Sahr's self-sacrifice ability before you're ready by dumping too many Thrulls into play.  Be aware, though, that Mourning Thrull is a Thrull too!