It's all about Tanksperience.

Another key element to being a tank is knowing the instance you're running.  As such, you need to do your research for all the bosses and know the pulls before you just run in head first.  Or at least have someone with you willing to guide you through it.  This is pretty key for survival.  Naturally you need a good healer and the DPS to kill everything, but that's not tanking is it?

Speaking from experience, a competent DPS can go into any instance having no prior knowledge about anything that happens in it and perform admirably as long as the tank knows the pulls and the healer keeps him up.  You just have to follow the tank's lead and focus-fire or AoE when it's called for.  

Now, I'm not claiming to be the greatest DPS out there, 'cause I'm not.  But I like to think of myself as a pretty good DPS for the gear I've got and I adapt to the situation quickly, situational awareness is something I pride myself on.  I can do over 2k DPS as both a Hunter and a Death Knight, and probably the same thing when I get my rogue up there, but it's kind of situationally dependent.  Franny will put out a higher damage quotient on groups of mobs (anything higher than 1 of 'em) due to the fact that his primary source of damage is Howling Blast which is AoE, and Tox is a single-target focus-fire DPS machine.

Back on topic: Tanking.  As a Death Knight your primary threat generation on groups of mobs is undoubtedly Death and Decay, it doesn't matter what talent build you use.  However, single-target threat generation varies greatly between the different builds.  With Franny's current spec his top sources of threat are Icy Touch and Howling Blast with Rune Strike as often as possible in there as well, along with a smattering of other skills (Plague Strike for Desecration, Blood Strike to proc Blade Barrier).  Other builds would use their respective abilities depending on the tree they put the most points into, but I'm not any of those builds currently so I'll not get into it unless I figure it out and start talking about it.

Threat Generation isn't really an issue on single-target fights.  But I've had some issues with multi-mob fights due to a lack of realize how important it is to use DD.  While that's important, knowing how to pull long range is very necessary too.  Icy Touch.  That's your best option, you want to save the "HEY! LOOK AT ME!" of Death Grip just incase your healer (or some other squishy) grabs aggro and is about to get taken down in one shot.  You should also be a lot more creative than "Come here!" when making macros for it.  That's just way too over done.  Yeah, I know, you're pretending to be Scorpion from Mortal Combat, but that's just a cheesy rip off.  Come on people, I know you can do better than that.

Yeah, that's basically what you need to know when you start tanking as far as skeelz in relation to my spec go. And here's what I've tanked so far, keeping in mind that I never tanked anything until 3 days ago and haven't done anything lower than Heroic.

Azjol-Nerub

Ahn'kahet: The Old Kingdom

Gundrak

Drak'Tharon Keep

Halls of Lightning

and Violet Hold (Pfft, that one's a joke)

I'm still looking for some more gear from heroics, and hopefully I'll be able to find people for Utgarde Pinnacle, so wish me luck.  I'm off to go in search of gear.

Good Hunting,

Tox