Levelling secondary class with no more quests?

[Erendis]

1. Hunting log. Separate for every class.
2. Guildhests. Every class gets first completion bonus.
3. Leves.
4. Fates.
5. Challenge log.

[Niwashi]

1. Hunting log. Separate for every class.
2. Guildhests. Every class gets first completion bonus.
3. Leves.
4. Fates.
5. Challenge log.

These are pretty much it for reaching level 15 (if you're out of side-quests). To continue leveling after 15, dungeons will be your best XP source. (These others remain useful secondary sources, though.)

[Magistrella]

These are pretty much it for reaching level 15 (if you're out of side-quests). To continue leveling after 15, dungeons will be your best XP source. (These others remain useful secondary sources, though.)

the amount of exp you can get over time hugely varies on the speed of dungeons entries you get which makes it best to worst (considering damage output and waittimes and stuff):

tanks: dungeons > fates > leves > hests > huntlog > challenge log
heals: dungeons > leves > fates > hests > huntlog > challenge log
dps: fates > leves > dungeons > huntlog > challenge log

so yeah, if you level a dps dont rely on the dungeon entry, you probably have gained another level with FATEs until you actually get a entry on low lvls <.< Not that it gets any better until 44 when you can dzemael 1st room farm.
Personally i have leveld all my classes (except pld -> quests, and whm dungeons) with FATEs. Hell i leveld all classes (except ninja obviously) to 50 with FATEs before roulettes were introduced, i didnt have the luxury of daily bonus exp from dungeons ^^ and hests only gave bonus exp once too ><

Yes it was a grindfest, but hey, endgame isnt that much different ^^"

[Niwashi]

Hell i leveld all classes (except ninja obviously) to 50 with FATEs before roulettes were introduced

Well, before Roulette was introduced, FATEs were the fastest way to level (and way overused as a result). But then with the addition of Roulette and along with it some major boosts to in-dungeon mob-kill XP, dungeons surpassed FATEs for leveling speed.

So, even for DPS jobs, you want to run dungeons as much as possible if your aim is leveling up. The fastest leveling is probably to stay either in a dungeon or queued for one continuously, while doing FATEs and/or leves whenever you're waiting in queue. (If you choose the region to FATE in based on where most of your hunting log targets are, you can probably knock those out along the way.)

[Magistrella]

So, even for DPS jobs, you want to run dungeons as much as possible if your aim is leveling up. The fastest leveling is probably to stay either in a dungeon or queued for one continuously, while doing FATEs and/or leves whenever you're waiting in queue. (If you choose the region to FATE in based on where most of your hunting log targets are, you can probably knock those out along the way.)

Fates still are the fastest way if you got a group going that's doing them. Especially from 34 on when you can dive into coerthas. That svara chain plus those quick dropping boss fates in the late afternoon/evening is faster then any dungeon where you'll probably have to deal with undergeared people. Especially cutters and vigil can be a 40-50 minute pain - if i keep fateing i'll have 1 level easily done by then :x and if you do Brayflox if you're over 36 the exp will be minimal compared to what you can get outside :/

[Erendis]

The maximum leve amount you can have is 100, so use some if you get there, or they will go to waste

These are pretty much it for reaching level 15 (if you're out of side-quests). To continue leveling after 15, dungeons will be your best XP source. (These others remain useful secondary sources, though.)

My assumption was that OP wanted to level thaumaturge from lvl 13 to 15 to unlock their job, therefore I skipped dungeons.