what i do is get crafting to the point where you can make either gold rings or emerald rings, then make gold rings / emerald rings. they're decent xp and very nice money.
from the last i could remember emerald rings doubled your money but you couldn't make much of them.. free trade coming out isn't gonna help that method, sadly. Miners will probably overcharge for their emeralds.
i'll find a better way sooner or later.