True, I tend to feel the push near 40, but it still isn't terrible. I can gain a level/day even on DPS, and that's off hours on my server.
One roulette usually does it, and then if that's not enough then one run of the highest level dungeon usually pushes me over the level threshold. Combine that with the challenge log, leves, FATEs, hunting log, etc and you're good.

Make sure to eat food, get rested bonus too. If you're in an FC ask them to turn on the leveling bonuses.
Good luck