When illustrating the card, I usually come up with the idea for it around mid-October and start gathering reference. This years reference comes from multiple sources - from internet photos, to family photos of myself and my girlfriend as children.
Unlike my comic work, I rarely do a rough thumbnail for the Christmas card. Instead I just jump right in because I have a pretty good idea where I'm going before I start.
After the initial layout I start my rough sketch.
Every year I try to do a different technique, and this year will be no exception. I will do another update on this when we are closer to the holiday. Until then, please take a look at cards from past years, HERE