I will say this, as a glad, it can be really hard to hold aggro of an entire group until lv 22 (provoke). Depending on how much the healer spams heals. Then it gets easy at 26 (with 3rd part of the eminity combo).
Make sure to move a few of the target icons to a spare bar (I just use 1, 2, and 3). If the dps is can count to 3 there shouldn't be a problem, but with a CNJ or WHM spamming medica (group heal)it is impossible to hold agro from the extra mobs even at lvl 35. Few healers realize this in an emergency heal that should only be used on the rare occasion the party takes an AOE. As a CNJ I always made the tank the priority and single target healed, even when the ignorant archer pulls the #2 mob from the group. Sometimes I would have time to throw him a heal, others he would take a dirtnap. This gets much messier when a mob breaks away from the pack and Medica is used. Now instead of the tank and dps fighting over agro the healer is being chased around the room by the entire pack.
For tanking, open up with (2) flashes then progress through a combo on the #1 target. By this point you can start rotating through the other two mobs and use provoke or combos to keep them on you. If you still ave problems due to healer agro or a dps is just doing as they please, you can always spam flash. The only draw back to that is the entire run will take longer now that you have to wait for mana regen between packs. Tanking and healing are more about the rest of your party playing together and less about the individual class.
I changed from CNJ to GLD in early access since tanking is just more involved. You have to work to keep agro in this game, but you are still always going to be heavily dependent on the rest of your group.
ETA: If you have a gaming mouse, set your target icons to the spare buttons. This helps when a boss summons adds mid fight and you need to create a kill order for your group.
This post was edited on 9/5 at 12:38 pm