No, I'm a Gladiator. Maybe I need to go back to Ul dah and do more of the class based quests...?
Flash is your AoE hate skill.
Mark the target you'll be focusing on as 1 (you can drag the 1 mark sign from the Signs menu right onto your hotbar).
Pull with your shield throw, or simply move into melee range.
Face the mobs away from the party.
Hit them with Flash 2x/3x, then go into your single target rotation on your primary target, interspersing interrupts/cooldown buffs/whatever else you need to use.
Remark the next kill target as 1.
Add comes into the fight? Shield throw and bring it over, if its any duration into the fight, the other mobs will already be locked on your and you can do an enmity+ rotation on it once or twice to lock it onto you.
Tada, you are now a magic awesome tank.
Be aware that Flash does have a pretty short distance, so you want to cluster the mobs up first before you fire it off. If DPS are yanking mobs off you before you can even establish initial aggro, that's their problem, not yours. If your healer is yanking mobs off you, get them back on asap, but it shouldn't happen for anything other than uncontrolled adds.