Presents drop off mobs in the dungeon.
Subsequent dungeon runs will get you 5 presents from the chest, depending on what you choose. Then theres the presents from the mobs...again.
Farming Orr as normal means more presents as the drop rate is good.
Buying more presents with the currency youve acquired from opening presents means...well....more presents.
Spending a bit of silver in the trading post means more presents.