The skull of tanking

The standard marks that I use is a simple kill order, skull, then cross, then star, then square, and then moon.  I expect star, square and moon to be crowd controlled.  There are a lot of CC options, but the classic would be rogue sap the star, hunter trap on the blue square, and mage polymorph on the moon.

If you don't have a kill order, then players will split their damage instead of creating a focus fire on a single mob. This will make trash take longer and make the tank scramble to maintain the attention of multiple mobs.  If the players follow the damage order the tank's job will be much easier, the healer will use less mana, and the group will move faster through the dungeon.

I also like the CC to happen after the tank pulls (expect for rogue sap of course), instead of "sheep pulling" as many people refer to it.  There's always going to be the beat of time between the sheep's polymorph and the tank gaining control.  This beat of time, is very dangerous, especially if you have players laying into the targets fast.  Instead let the tank pull, then lay down the CC.  The player doing the CC, needs to worry about where they are going to CC the mob.  Casting polymorph on a mob that is sitting next to the tank isn't a great option.  If the tank range pulls the group, this usually gives plenty of room for the CC to take place while giving the tank plenty of room to cleave.