Get and check AtlasLoot for each instance and start choosing the ones you want to run for the kind of drops you can’t easily buy. Check AH regularly for decent deals on big upgrades.

And as a DK tank, get the biggest, baddest weapon you can. A green +def axe is no replacement for the threat generation of a decent epic from ToC or PoS which will also allow you to hit mobs.

For running normal instances, I still wouldn’t do that on 449 def for the 80 instances. VH, DTK etc. would be fine. I would recommend running almost exclusively ToC, FoS, PoS and HoR as dps until you get the drops that the tank doesn’t need. These are fast, good epics from these instances which will gear you up quickly. By the time you have about 510 def, you’re more likely to have the kind of gear that gives you enough stam and avoidance to tank these without killing your healer’s mana pool on every fight – just make sure you know your threat rotations, and probably best to avoid HoR until you’re competent and have a beautifully set up tanking screen

A tanking display makes life easy btw. I have Power Auras set up to give me a 5 sec countdown when I need to reapply diseases, which of my 2 main big hitters (heart strike/death strike) are available, death grip, dark command, Death and Decay etc. are all on there, along with the “reminder” boss talents such as Hysteria, Empower Rune Weapon, Vampiric Blood and Blood Tap, along with warnings when runic power is at 80 and 100% to let me know when to dump it. It also shows when I’m missing Horn of Winter or Strength of Earth (totem), which helps keep your threat and avoidance up that little bit higher.

http://www.tankingtips.com/2009/12/24/the-emblem-of-frost-pick-order/

The rest are found at http://www.youtube.com/user/Grendalsh

The principles can easily be transferred to the G13. Highly recommended!