Leveling without leves?

[Thaliss]

Yeah, Free Company action, 5% or 10% depending on lvl,
food xp bonus.
Grand company xp book.
Grand company supply mission, Click timer, once per day.

And my favorite.
Why don't you level up crafting stuff for gil? or for you own use?

Exactly
When I am anticipating to do leves I usually craft the basics materials (ingots, threads etc..) in rather high quantities with grand company xp book.
Doing so I usually don't use much my leves.