Just as a reminder, there is one item in particular that always sells well the first few days of the holiday: Small Eggs. Today's your last chance to head out to one of the lower level zones and kill a few thousand birds (or bird-like oviparous creatures) in order to make your fortune. Remember that you'll need at least five eggs yourself in order to complete the quest that creates the clamor for these items in the first place, so even if you don't wish to make a killing on the auction house, it would probably be wise to grab some eggs before the farming gets out of control. Check out Robin's earlier article for a good tip on a farming spot as well.
It might also be wise to stock up on some Deeprock Salt, since it's used to created Preserved Holly. This item can only be created via a quest that is only available during Winter Veil, so now is your chance to stock up and sell the items on the auction house at an inflated price once the holiday is over. I honestly don't recall if the salt was selling for a high price last year, but I would imagine that it would see a higher demand this year since the Holly can now be used with flying mounts.
What are you most looking forward to this year? Are you planning on being an egg and cookie magnate?