With all the arguing about Death Knight tanking I thought I'd throw my two cents in. I'll explain talents, glyphing, rotations, stat priorities and gear. Now obviously everything is up for debate, if you disagree feel free to comment and share your thoughts my only request is to be respectful. Yes I am new, that doesn't mean you can use that as an argument of why this information is false. It's a very long guide so grab a pepsi and get started. Without further procrastination let's begin.
Talents and Glyphs:
For talents most decisions are pretty straightforward. Abomination's Might isn't really that important as other classes can supply the buff allowing you to use those talent points in a more necessary area. You'll want Sanguine Fortitude for sure, during heavy damage areas in fights popping Bone Shield and Icebound Fortitude (even like on the trash before magmaw right as the mobs are switching between you and another tank use them both to mitigate damage and afterwards pop as many death strikes as possible as that's when you'll get max self heals). We have Lichborne for self healing (see macro section) Endless Winter is great in 10 man's to help out with interrupts and we put the rest of our points in Epidemic.
As for glyphs, those are simply what I recommend. Always keep some dust with you to switch out if necessary. The only glyph you absolutely should have is Vampiric Blood. I usually say to keep Rune Tap on as well, it's especially great in the Chimaeron fight. But if you have other glyphs you'd prefer it's not a big deal, but you should keep Vampiric Blood and Rune Tap on.
Rotations:
So now we have the tanking rotation. We have two rotations here, Boss/Single target and Trash.
Single Target -
Outbreak
Death Strike
Heart Strike
Death Strike
Trash -
Death And Decay
Outbreak if it's up, else Icy Touch then Plague Strike
Now you'll notice these are fairly short rotations. That's because those are simply how you should open up. After, you begin having a priority system. Meaning there's a list of spells you want to use first and if you can't or don't need to then you continue down the list until there is one. Here's the priority,
1. Diseases - Outbreak if it's up, else IT and PS, if trash Pest.
2. Death Strike - If appropriate, use a Death Strike. Only if you still have runes for another when you'll need to max self healing and mitigation.
3. Heart Strike/Blood Boil - If trash Blood Boil, if Single Target Heart Strike
And that's about it for spells.
Stat Priorities:
Stat priorities is where things get into the grey area, people have different ideas about what's better but I'll try to explain myself.
1. Mastery
2. Dodge
3. Parry
4. Hit
5. Expertise
6. Stamina
7. Strength
8. Crit
So we have mastery as the most important. It really is, if you can learn to time your death strikes and control your runes just right it will be your biggest damage mitigation. Next up is Dodge, it's higher then Parry because Death Knight's get a lot of parry through talents and abilities. Due to diminishing returns, dodge is wanted more then Parry. After parry is hit. Most people say you should be hit capped, but I am far from it and never have threat issues. If you are having threat issues, perhaps you may want to grab some extra hit. Expertise follows because it's extremely easy to hit the soft cap which is really all you need. The soft cap is when there is a 0% chance for a boss (level 88 is raid boss) to dodge you. This is 50 expertise rating for most people, unless you are an orc with a fist weapon or axe, dwarf with a mace, or human with a sword or mace then it is only 47. 120.1088 expertise points from gear gives you 1 expertise rating at level 85. Keep in mind of your talents etc. the best way to tell is look at you character selection screen and see how far you are from being capped. Stamina > Strength but you don't necessarily want to stack it. Strength is > Crit (which you should have any of, I figured the newer players it might help).
Gear:
Here is, in my opinion, the best gear set for regular raiding. It's what I personally am going for.
Main Hand
Akirus the Worm-Breaker - Magmaw, Blackwing Descent
Ranged
Relic of Khaz'goroth - Valor Points
Head
Daybreaker Helm - Valiona, Bastion of Twilight
Neck
Ironstar Amulet - Atramedes, Blackwing Descent
Shoulder
Magma Plated Shoulderguards - Cho'gall
Back
Wrap of the Great Turtle - Guardians of Hyjal
Chest
Magma Plated Chestguard - Valor Points
Wrist
Bracers of Impossible Strength - Halfus Wyrmbreaker, Bastion of Twilight
Hands
Magma Plated Handguards - Valor Points
Waist
Hardened Elementium Girdle - Blacksmithing
Legs
Magmaw Plated Lagguards - Valor Points
Feet
Boots of Sullen Rock - Dragonmaw Clan
Ring 1
Ring of the Battle Anthem - Valor Points
Ring 2
Bile-O-Tron Nut - Chimaeron, Blackwing Descent
Trinket 1
Vial of Stolen Memories - Valiona, Bastion of Twilight
Trinket 2
Symbiotic Worm - Magmaw, Blackwing Descent
If you disagree with a choice please state below what you would choose.
As for reforging, gemming and enchanting, you shouldn't need too much reforging, any excess expertise/hit perhaps you can put into mastery or if the gear has mastery then dodge or parry but that's about it, it's pretty much up to what you think you need more in that circumstance. Gemming you should have an Austere Shadowspirit Diamond in your meta socket, a Retaliating Demonseye in any red socket, and for blue, yellow and prismatic sockets put a Puissant Dream Emerald. Enchants are honestly the least important thing as the stats are extremely great on them to make you an amazing tank, but that isn't to say you shouldn't get them. Just look around at enchanters for what you see usefull, don't waste your gold getting the best enchants because the best enchants aren't going to be that much worth the gold you might have to pay for it. On my server Maelstorm Crystals are around 1k a piece. No use paying that much plus the dust and other things for 50 mastery points. But if you get it for cheap definitely enchant your gear, just don't worry about it too much. If you really want the best enchants, look your character up on wow-heroes and it'll recommend some for you.
That concludes my guide to a blood Death Knight. Blood DK's are in my opinion the most fun tanking class. Good luck and have fun!