What makes you happy as a DPS or healer? Can you envision how that looks in play?

Okay, now you just have to reverse-engineer it from the tank's set of tools.

Seriously, though, that really is it. You'll generally learn more about proper tanking from healing and DPSing than tanking by itself, and in some cases more about healing from tanking, etc.

Pull as many packs as you can reasonably AoE down; Sprint before you aggro the first mob in a set of packs for double duration on the Sprint; don't scoot mobs out of your ally's AoEs or lines of sight; don't take so much damage upon gather that your SCH can't Bane; keep the mobs as tightly packed as possible; spin them minimally; in a pinch during a gather, feed your Monk a stunned mob for the GL upkeep if you already wasted his Sprint; etc., etc.

In short, avoid the stuff that annoyed you when trying to play well on a DPS or healer. Take advice from others in case you were abnormally hard to annoy so that you can meet more refined or optimized tactical tastes.