A tradition is just something someone kept doing long enough that it outlived them.

Nothing begins as a tradition. Somebody made the same cake twice, or insisted on the same walk after dinner, and kept at it through the years when it was mildly inconvenient. Repetition is the entire mechanism. What feels ancient and solemn in a family is usually one stubborn person and a long run of Decembers.

If there is something you like doing with the people around you, do it again on purpose this year and say out loud that it is now a thing. Being the one who insists is unglamorous, and it is exactly how these get made.