FATEs solo while Qd for low level roulette or dungeons,

after you knock out low level roulette (which has a nice exp bonus)
you can keep solo fate farming, while qd for dungeons or join a party
for fates. Whichever suits your preferences.

the guildhest also rewards each class you can level, but sometimes the Q
on it is very long.

Be sure you have the challenge log open, it comes from a quest in limsa
adventurers guild. bonus exp and gil is never a bad thing.

I did a combo of fates and low level roulette for the most part on the
last class I leveled.