The weapon you use while tanking is important. If you refer back to the previous article you'll see I mentioned Heroic Strike as a threat builder. A lot of warriors love to use HS spam to hold aggro and for that reason a fast tanking weapon is useful. I'm personally tanking with a 1.4 speed weapon now. If you can get stamina, defense or +hit on your weapon, by all means do so. In general, +hit is a nice stat for a tank, because you can't build threat if you're missing everything. One bad miss streak and one lucky hit from a DPS'er can equal aggro loss faster than you can imagine, so don't neglect +hit. Try and make sure you get enough hit rating so that your special attacks don't miss. I would say you want about 6% to hit, so roughly +96 hit rating at level 70. (If my math is off I apologize.) If you're having a hard time finding that much don't sweat it, but any hit rating is helpful.
The last time I talked about tanking in any detail, I was taken to task for not discussing Shield Slam. The reason I didn't is because it requires 31 points in protection, and I wanted to write a general guide for beginning tanks. But those that commented were correct in that Shield Slam is, hands down, the best threat generator a protection specced warrior can get. It only gets better the more shield block rating you have, too. The only down side is that somewhat hefty 20 rage cost. If it were up to me my first move to establish agg on anything I was expecting to tank would be to give it a nice shield slam, but sometimes I simply can't wait for 20 rage to generate, especially not when I have a triggerhappy DPSer or two in my party and I have to tank multiple mobs. As soon as I can, though, I slam a target.
One of the reasons I tend to respec at least twice a week is to get my hands on shield slam for tanking. Other talents like Defiance are accessible without too much investment in Protection, but shield slam is far enough down the tree that you might as well go all the way once you're there. I tend to spec 48 points in protection, leaving 8 in arms for Improved Thunder Clap and 5 in fury for Cruelty. Other warriors will disagree but I've never had cruelty leave my spec on any of my warriors, and I like imp TC for establishing enough snap aggro on trash to keep them off the healer, especially combined with defiance's 149% aggro increase in defensive. It's not remotely as good as what a pally or druid can do on multi-mob pulls, but it works for the most part.
I'm of two minds about Devastate. On the one hand, the tooltip fooled me for a long time: I thought that the threat generated by devastate increased if you stacked more sunders on a target. In a way it does, because the more sunders you have on a target when you hit devastate, the more damage it will do, and more damage does generate more threat, but there's no static threat increase for additional sunders. Devastate does the same threat if you have one sunder up as it does if you have five. When I'm prot specced I do use the big d, but it gets in line behind shield slam and shield block/revenge, taking the place of sunder entirely. Still, it can be spammed (only limited by the global cooldown), which shield slam cannot, and it's an instant. Nothing wrong with doing a little damage, generating some static threat, and keeping sunder armor refreshed all in one go.
One of the talents I most love to have when I'm tanking isn't even one of mine, it's a hunter ability. Yes, I'm talking about Misdirection. Much like taunt, I do find myself wondering how this ability works... does the hunter step up, shoot someone and then point to me and whisper 'he did it' or perhaps simply turns to me with an astonished look on his or her face and yell "I can't believe you just shot that dreadlord!" before moving back to, well, shoot that dreadlord? But however you want to justify it in game, misdirection is one of my absolute favorite abilities and I'm always glad to see the graphic pop over my head. It's on a two minute cooldown so, if you can arrange for a hunter to pull with this ability please do yourself a favor and ask for it by name. Especially if you end up tanking when you're not protection spec, this is an excellent front-end threat dump and instead of wasting the threat the way feign death does, the hunter dumps his threat onto you. If a boss fight is going to last longer than two minutes the hunter can even use the ability again, which can help a great deal if you're struggling to keep ahead of the DPS.
Concussion Blow and Improved Revenge are both indirectly useful for establishing and holding aggro. By themselves, they don't really have the threat punch of a Revenge or Shield Slam, but they do allow for two very important things: spell interrupt and limited crowd control. If you lose aggro on a mob and it resists taunt, stunning it and working up the rage for a solid shield slam is a nice ability to have. A mob that can't attack anyone while you slam and devastate on it to build threat is a mob that's not running amok.
There's a lot more to tanking than threat, of course, and a lot more to threat than what we've covered here. I'll want to come back and discuss mitigation at length in the future, and also take some time and discuss each move in the threat building arsenal from the two tanking articles more in depth. But we've covered a lot of stuff for now, so we'll end it here.