I know that the Warrior Stone helps. Also using a Daedric Mace does better than a Daedric sword. But does using a Bound Sword work even better? I could test it out, but then that would make asking in the first place pointless.

My understanding has always been the higher the base damage of the one-handed weapon you hit an enemy with, the more "XP" you pump into One-Handed.

If that's true in general, then since a Bound Sword has a lower base damage than a Daedric Mace or Daedric Sword, it will get you less XP.

I've found that one-handed levels much faster when dual-wielding.