What You Didn't Think About While Tanking

In wow there's Roles. You can of course further individualize them into style. Melee vs Ranged dps, HOT healers, vs Direct heals.
However it breaks down to 3 simple roles...
Tanks
Healers
Dps

From playing all 3 roles, I feel dps while it has its own niches, is a fairly simple fare.
Healers revolve around when and where to use what.
Tanking well... on the surface is very simple. You see the tank grab the mobs and hold onto them without dieing. That's all most ever see.

Nobody in the general community praises a tanks ability to just throttle up threat and grab aggro without a taunt. People just assume they got taunted off of. Even many tanks miss it.
Tanking requires a broad range of skills, needs, requirements, whatever.

Some main things every tank needs to have in their mental arsenal are..

1) Self Accountability: A tank has to admit when he does something wrong. It rarely boils down to you, but when it does... you have to own up to it. Another facet not usually thought of when you look at that point is knowing what you can chew off. Knowing your capabilities in gear allows you to look ahead at dungeons and figure out your ability to survive the damage. If your gear is in the higher end, you can pull through an instance faster with bigger pulls etc. If your on the lower end and realize it, you can use that info to dial back your pulls.

2) Situational/Tactical Awareness: Know ahead of time what does what, and how to maximize that to your advantage. If you see an alcove nearby where your engaging casters, you might want to think of drawing them in using that alcove to LOS (line of sight) them. As casters will not budge unless their unable to cast for a few seconds. Line of sighting them draws them in into one neat pack close together, enabling you to lay down solid threat on all of them at once. This is further compounded when you consider that there may be a pat walking around that could possibly aggro. Having those mobs pulled away becomes a great help.
Another facet is knowing whats going on around you. If you see someone inching near a mob they don't see, you can pull it before they aggro it. This prevents any haphazards. In the case of a hunter pulling it, their first instinct may be to feign death, in which case it'd go right to your healer. If it was a cloth wearer that pulled the reality of them dieing very quickly is a real possibility, with the same outcome of it chasing a healer. Pull the mob early and you cut that factor out of the engagement. The key here is to be able to react properly and quickly to situations that can and will arise.

3) Carve yourself a list of upgrades that are up ahead. If ptr is up check popular sites such as www.mmo-champion.com to see if they have loot lists on those new places up. Write those pieces down and their location in which they come from. If its just from a place you haven't beforehand adventured, its the same process, look at your atlas loot and find your upgrades, write them down and as same, their location of drop. You'll be ready to make your decision of looting when they drop, immediately. The main reason is that you won't have to guess if its an upgrade, you'll know ahead of time.

4) Rotation!: Having a strong fix on your rotation will allow you to output the very best you can in terms of threat. If you have a great fix on your rotation its another thing that you won't have to keep your mind fixated on. You'll have some of your mind free'd up to concentrate on other matters.

The basic idea here is to be in control the best your able to. A facet of tanking that's very important, the ability to control chaos. In the end that's the role of a tank, the sheer act of controlling chaos.
Tanking perhaps is one of the more thankless jobs in the game, however it provides what I believe is the greatest satisfaction. As Ciderhelm once quoted, "with the greatest risks, comes the greatest rewards.. and glory"