Hiya!
During the last few days I've been leveling my level 30 classes to 50, and I've found a method which is extremely fast. We're talking a level every 10 minutes, if not faster. We're talking Squadron Dungeons!
What it all comes down it is how Squadrons work, and specifically the action "Engage".
Engage
Now the way this action works is by telling your NPCs to attack and in doing so, among other things, they use their openers. Click engage again, and even though they are already engaged with a mob, it forces them to use their opener again. It also resets animations meaning there is no global cooldown between the usage of skills.
You see where I'm going with this? Spamming engage makes every single enemy melt. Bosses die within seconds of their areas closing off. This leads to some extremely fast dungeon clears. Especially with the right class combinations, seeing as Archer's opener is Barrage.