Experiment With a Variety of Main Jobs
On that note, it’s really important to experiment with all of the jobs you get in Bravely Default 2. While it might be tempting to just have Seth be a Vanguard main for the entire game, or have Gloria just rock White Mage and Black Mage the whole time, it’s useful to have them play around with other jobs for both passive and active abilities.
For instance, while Seth might excel with Vanguard as his main job, you still need to fill out his sub-job slot. Having him level up Bard, Thief, Red Mage, or Salve-maker are all really solid options as Seth’s a pretty decent all-rounder.
One thing you need to know, however, is that characters only earn JP for their equipped main jobs. This means that if you want Seth to get all of the Red Mage perks when equipped as a sub-job, you’ll still need to equip it as a main job for him first. Once he’s gotten enough JP to max it out and get all the skills, set it as a sub-job and put him back on whichever main job you want for him.
The stats will be scaled back to whatever the main job entails, but he’ll still have all the Red Mage perks available in combat. It’s also worth noting that passive abilities can be equipped regardless of a characters main or sub-job.
This means that if you level Berserker enough on a character to get the Unshakeable Will passive ability, you can put that on your character and ditch the job entirely.
Similar to Octopath Traveler, it’s definitely worth your time to try to level several jobs on each of your characters to get some seriously good passive abilities that will make your party unstoppable.