World of Warcraft DPS Basics

• Presence
  Blood, always. Unholy is for PvP. Frost is for tanking. Keep your damn Blood Presence on when you're DPSing.
  
• Pestilence
  Using Pestilence to your advantage on trash packs is a very good use of a Blood Rune, even if you don't have Epidemic. You're essentially multiplying your disease damage by however many mobs there are, and also setting up your next target so you can immediately move into your main rune attacks (HS, OB, SS).
  
• Trash "rotations"
  There are no real rotations on trash mobs; when people talk about rotations, they mean on bosses, where you're generally sticking on one target and need to maximize every single bit of DPS you can get. This applies to what I was just talking about with Pestilence; you're not always just going to be blasting away with PS/IT/SS/OB/HS/BS. You're going to need to use other abilities.
  
• Blood Tap
  Lots of Blood DKs don't think this ability is useful for them; au contrare, mon frère. This ability takes a Blood Rune and turns it into an active Death Rune, regardless of whether that Blood Rune is on cooldown. You can see already that this is worth it slight bit of HP that it'll cost you to use it, I hope.
  
• Death and Decay
  I know it makes a really cool noise, it's an AoE, and it looks really trippy, but it's terrible rune use and terrible for DPS, on top of causing a metric crapton of threat. Don't ever, ever use it when you're DPSing.
  
• Raise Dead
  Yes, there will be times when you should be using this. Most bosses will allow you to use ghouls. The thing to make sure of (which I'm not) is if there are player-activated things like Flame Wreath on Aran, will the ghoul activate them? If so, I'd only use your ghoul briefly and Death Pact him as your first "pot" to gain 20% of your HP. Keep in mind as Blood and Frost, you cannot make your ghoul follow you; as Unholy, you can, but you lose a lot of DPS if you DP it.
  
• Hysteria
  Goes on your highest DPSer. End of story. I don't care if you want it for yourself, it goes on the highest DPSer in your group for that boss. We're min/maxing here, folks.
  
• DRW/Garg
  DRW/Garg are only used at 100 RP. Once you use DRW, you can then go back to your normal rotation. With Garg, you cannot dump RP until the effect is over. Dumping RP on DCs will not allow the Garg to stay for the full minute possible duration.
  
• Icebound Fortitude/Anti-Magic Shell/Lichborne
  These aren't just PvP abilities (admittedly, Lichborne is more PvP-oriented). IBF reduces all damage by 20% (and gains additional damage reduction based on defense value) in the duration and has a 1 min cooldown. On bosses with an AoE, use this to soak some of the damage if you can't avoid it. AMS reduces all spell damage taken by 75%, and can possibly generate RP for you (though if you're generating RP from this ability, odds are you're doing something wrong). For Lichborne, other DKs can heal you, and for bosses that have fear mechanics, they often have a cast time. Pop Lichborne before you get feared, and voilà.
  Builds
  
  Keeping in mind that this is a PvE and end-game oriented FAQ, let's leave leveling and PvP discussion to other threads. This should be about min/maxing DPS. That said, there are a few DPS builds that I'm aware of (and PMs to send me links to EJ threads about other builds are appreciated).
  
  
• Diseaseless Blood (51/0/20)
  
  The basics of this build are simple: use HS, OB, and DC. No diseases. FU runes are used in pairs; when they're actually FU, use OB. When they're death runes, use 2x HS. Nothing very complicated with this build, yet yields high DPS at high levels of gear (i.e. T7.5).
  
• Frost (21/50/0)
  
  Pretty simple build, again.
  
  DRM is a questionable choice and has been debated a lot by a lot of different people, but it's there to be there. If you don't like how the build plays with DRM, change the points to Imp Rune Tap (1/1 Rune Tap, 2/3 Imp Rune Tap). Basically there for movement fights where you may have to 6x IT before you get to move back in.
  
  Rotation:
  Using HB as Rime procs,
  PS/IT/BS/BS/OB/RP dump
  PS/IT/OB/OB/RP dump
  
• Unholy (17/0/54)
  
  I'm a bit shaky on this build (don't know whether people still use Desecration or not), but this is the build that's the most forgiving on gear, and should be used for a while until you get better gear/weapons and can switch to Frost (moderate gear) or Blood (good gear).
  
  Rotation:
  UB indicates using Unholy Blight before moving into a DC RP dump.
  IT/PS/BS/BS/SS/UB/RP dump
  SS/SS/SS/RP dump
  
• DW build (0/32/39)
  
  This build is dying in patch 3.1. I'm not sure on all the salient points of this build, but were I to try and max DPS DWing, this is what I'd go for first.
  
  Note with the 5s cooldown on HB, it's usually best if you dump RP as you get it (i.e. 40 RP for DC), otherwise there's a pretty tremendous DPS loss.
  
  Rotation:
  PS/IT/BS/BS/HB/RP dump
  HB/HB/HB/RP dump
  
• Death Runes
  
  They need their own section. Each tree will have their own Death Runes, which are runes that switch from their normal form to a "Death Rune" which can be used as any type of rune. Death Rune Mastery (DRM) in the Blood tree converts an Unholy and a Frost rune to a Death rune each time an FU ability (DS/OB) is used, allowing for more HS in the second section of the rotation. The other trees have much the same in the talents "Reaping" (Unholy) and "Blood of the North" (Frost).
  More to come.