This thread should be here: http://www.tankspot.com/forumdisplay...-I-need-advice
Here is my work on the topic:
Frost works rather like Warrior tanking in that you are using a priority structure with procs to look out for. Here are some simple guidelines to get you started, assuming you have a fairly straightforward spec.
1.) Two slow weapons are ideal threat. Using tanking weapons in one or both hands will potentially give you more survival values but they'll do as much as 15-20% less threat overall compared to slow weapons of the same ilvl (though they'll be closer to match slow weapons that are a full tier or so below, i.e. ~19 ilvl difference).
2.) RS should be used on every availability. It is the best use of RP for threat, bar none. To that end, try to avoid using Frost Strike unless you have more than 60 RP (52 if FS is glyphed).
3.) Rune cost moves are always your first priority. FS as your RP burning ability should only be used when all your runes are on cooldown, with one exception: Killing Machine procs. On single targets you will want to use KM procs on FS, and on Howling Blast for AoE groups.
4.) If you have Blood runes (not currently Death runes by Blood of the North), you'll want to BS for single target threat, Pest to spread diseases, or BB for AoE threat. Beware: BB will not generate Death runes.
5.) Your default move for Frost/Unholy pairs or Death rune pairs is Obliterate on single targets and HB on AoE groups. Regardless, if HB is on CD you want to use OB as it can proc the Rime talent and refresh your HB and make it free to cast (think Sword and Board).
6.) Diseases are your first and most important step. If they are not applied or are about to fall off, they need to be refreshed/applied. Frost Fever (via IT or HB if glyphed) is the most important. FF will buff every move except OB and Blood Strike to their maximum values. If you are dual wielding slow weapons it is still well worth your time to apply Blood Plague (via Plague Strike) as it will offer a solid bump to OB/BS threat.
7.) Always use Rime procs (called Freezing Fog if you track it with an addon) before using OB again (like SnB), even on single targets.