In my family Christmas Eve is a bit more casual. We relax, go out for Chinese food, and just hang out. I still like to dress festive but I go a little more casual. I love these vineyard vines pants, they are super festive and they are now on sale just in time for Christmas! I paired them with a simple grey sweater, this cashmere is so soft and warm! The tartan cuffs on the sleeve are probably my favorite part of the whole outfit. This look is perfect for my friends in the Northeast, the cashmere is so warm and pants are perfect for those freezing nights! Festive yet casual perfection. 
I have a few pairs of tartan pants and I love the color on these. They ran a little small so I would size up! Vineyard Vines did such a great job on their holiday line this year! Big thanks to vineyard vines for making sure I looked my best this holiday season, as always all opinions are my own.
My coat is J.Crew, unfortunately it is currently sold out but J.Crew always has a bunch of great coat options, and my shoes are from Talbots!
You look very festive and I love your coat.