The time in between Christmas and New Year is for rest and retreat.
It may be actual retreat; yoga, vipasana. It might be an at-home retreat; shutting the doors and quietly pottering away with the remaining December tasks in an unhurried way, and taking long rests. It could be going away somewhere peaceful just the 1/2/3/4/5 of you. Whatever. Rest and retreat. Like the earth does then.
Then New Year needs a Ritual. On new year yoga retreats we get given a list of questions to ponder on the 29th. On the 31st we do a partypiece party, where everyone does a party piece, which is diverse and surprising and delightful. Then we write down the things we are choosing to leave behind in the departing year on little pieces of paper, and at midnight we burn the paper in the fire. Then we talk together about what we're letting into the coming year. I've done it twice with Alaric and each time it has felt special and seems to have had a really nice impact on my life.
The two months of the year where most of us (ideally) put the least energy into trade are August and December. In August we put most of our energies into the land, and in December we put most of our energies into our relationships, from our relationship with our world and community, through our friends, family and partners, to our relationships with our selves.
Both periods precede New Starts and both are full of holiday, festival and celebration.