Okay i dont like blood dks and i really loathe the fact that they exsist out side of PvE, but it exsist and you will play it because you have short fingers and can only press 2 buttons. Im only writing this because i see people saying,"Hw play Dk blood spec, i retail 2.6k 2v2 r1 blood dk". We can see you arent but anyway this should get you going in your fail crusade.
First thing is viable comps for blood dks.
Blood DK and Blood DK.
Nothing else is viable.
Okay now, your going to need some stat priorety.
Hit cap(5%)> Spell Penetration (at 190) > Mastery > Resi > Strength.
Mastery basicly makes you absorb more. It stacks to your maximum health. This is called a blood shield.
Use this spec. Not sure if its the best but your a blood DK deal with it.
Glyphs are in the link.
Now with gearing.
Since this is a bad spec to play im not gonna even go to wowhead.
Just take all the Accesories with mastery.
Enchanting go straigth for mastery, then go stamina or strength.
Reforging go for mastery. (Unless your not hit capped)
Blue = 44 spell pen (3x)
Red = 17 Strength and 17 Mastery
Yellow = 17 Strength and 17 Mastery
I go with enchanting/leatherworking for the 190 stamina.
Tailoring for the 1000 AP or just enchanting or LW for another 190 Stamina.
Doesnt really matter though.
Ok now what you have all been waiting for
Well here it is in an order of importance.
DoTs.(Dont bother agaisnt healers, they can just dispel with no problems)
Then Death Strike a few times.
Then see what ever is off CD spam that till you get Death Strike off CD.
Then use blood tap and use Death Strike some more.
Kinda like that.
Then here are some macros.
Just use these to tell people you use macros and create the illusion you have a brain.
Now for the most important part...
Always use unholy presence, increased movement speed, rune regen and glyph of dark succor are the only reason really.
Okay so that should be about enought to teach you how to play with the basic rotation.