I agree tanking requires the most knowledge cause 90% of the time we have to lead and explain fights, but once you know the fights they are pretty easy to play. When I was first leveling, my main was a tank so I had instant queue, but before every dungeon I always read up on all the fights before I actually do them, so I can explain fights to others (this was back when ARR first came out so everything was pretty new to everyone). People always expect the tank to explain fights for some reason, so that's what I ended up doing alot of the time. Since you already have SCH leveled, it will be alot easier for you since you will know all the fights and will have the XP bonus.
One of the most important thing for Tanks is gear. If anyone tells you gear don't matter, its all skills, yada yada, they probably never tanked before. Your gear has to be up to date or you won't be able to hold Enmity on good DPS no matter how good you are. I will suggest you to get at least get around an ilevel of 100 (110 is best) before you start doing Expert roulette, or people will rage.
When you pull always try to stack the mobs together for the DPS so they can AOE easier. Try to limit movement except for when you have to dodge, this is more important if you have Melee DPS in your group, you don't want to turn mobs too much or it will mess up their rotation. If you group is all ranged, move as much as you want, just try to keep mobs in the AOEs.
For healers just keep an eye on their MP, for normal 4 man dungeons, you will generally not worry too much unless your group is undergeared or if the Healer is DPSing alot, which happens often in geared groups.
Otherwise just remember to use your CD's when you need them. Be nice and courteous, but this applies to everyone. Honestly its not too bad, you just have to practice it and it will come pretty naturally.