If you do a dungeon that's your level, you get the chain bonus for killing mobs. This practically doubles the xp from the dungeon.
Not to mention the first time completion that you may get (can't remember if it resets by job).
I know the guildhests have a first time completion bonus by job as well, though it's less than the very first character I think.

The challenge log is also a ton of bonus xp, even though it resets weekly.
With the armory bonus (+50% xp), it's not that bad of a grind. I felt so for my second character being accustomed to having more quests but I got over it when I got accustomed to the system.

- Do a dungeon the same level it unlocks (that's almost a level, if not a level)
- Do the daily roulette (dungeon and guildhest), that's about a level
- You can do fates and leves in between, but don't use your leves during the same level as a dungeon unlock (less efficient)

At level 32 on, dungeons unlock every 3 levels. What I said above grants at least 2 of those per day.
That means you just need to grind one extra and repeat.
If you're really power leveling, then you won't be able to repeat the roulette if it hasn't reset yet.
The Challenge Log will give great bonuses during this process. It's best to complete it as late as possible for some since the xp scales really well with level.

I won't be surprised if they nerfed the time it takes to reach 50 for the expansion, but the grind only feels bad if you don't keep objectives in mind.