why do you want to be like the older players? just do your own thing, pick a class and make sure to level up the sub classes so you get the cross skills. I've been playing 6 months+ now and I still don't have all my classes maxed nor do I want to.

levelling from the dungeons can be a pain with roulette so just do fates.
1-18 west thanalan
18-25 quarrymill
25-30 costa del sol
30-35 coerthas
35-50 north thanalan

also when you think that the fates are empty just think of the others who are in the map as well thinking the same. just yesterday no fates were being ran in north thanalan and the moment I started one of them at least 5 people came running to jump on the band wagon.

levelling arcanist is slow before lvl 30 so make sure you upgrade your job after to scholar, then you will get almost instant access to dungeon runs with possibly at most 5-10mins max wait depending on where you want to go