Only one thing that sorta bugs me about those suggestions: "You should always be the group leader, if the healer or dps in your group doesn't understand that then you don't want them in your group, they are not astute enough to play the game and they don't know the rules." I mean, yes, as a tank you should absolutely know how the pull will go, so being assertive if you don't think everyone on the same page IS necessary. But at the end of the day, there's worse things in the world than letting the main assist/CCer set up the marks, particularly if they know the instance better than you do. You're the tank and you should definitely know how to do the marks in any given instance, but as long as it's getting done it's not really worth getting into a pissing match about it.
James covered an awful lot, so really I only have couple generic suggestions that are mostly 5 man related; bosses and raids are less likely to be tank 'n' spank affairs and thus follow their own rules.
1. Always have an ideal tanking spot in mind, because in 5 man content adds are far more likely to get you killed than being sloppy with your abilities or making a goofy gear choice or two. One of the reasons James' and other tanks do things like "shoot a mob, walk backwards and then charge" is because it helps to keep the fight right in front of them and because they already have a "safe" spot in mind in order to avoid patrols. The more players and hostile mobs you have spread out over a large area, the easier it is to accidentally pull yet another mob into the fight, and getting adds is the quickest way to cause a wipe in all of WoW. Meanwhile having everything in a relatively small area* away from other mobs is a good idea because the melee gets to spend more time swinging and less time switching targets, the casters don't have to worry about casting range and fleeing mobs have to run farther before they can cause any mischief. And of course, you have an easier time keeping track of where everyone is in the room. Everybody wins.
2. Learn how/when to line-of-sight pull, since it helps you with my previous suggestion. Ranged mobs are often a pain in the ass because they like to just stand there in the middle of the room, threatening to attract other wandering mobs. In this case you may want to draw aggro and then turn a corner or run behind a pillar so that the mobs need to approach you before resuming their attacks. It's often unnecessary, but it's a good trick to keep in mind.
*You don't really want to pull mobs inside of melee range of the healers/ranged dps; that's a bit overkill particularly since many mobs have cleaves or AoE abilities like whirlwind. Just another good reason why it always pays to know what kind of mob abilities you have to put up with BEFORE you enter an instance.
