All Orthodox, celebrate Christmas on 25 December, the date differential is simply a matter of which calendar (Julian or revisied Julian).
Christmas is generally preceeded by a fasting period. This period is more relaxed than Great Lent, but some are still fairly strict. As for "celebrating the season", it varies greatly from person to person family to family.
FWIW, my personal practise is to avoid most of the secular aspects and parties/dinners. I do however remember not to be pharisaical. I always strive to exercise Christian love and charity, especially in regard to non-Orthodox family and friends. When I do have to attend an event or dinner, I try and keep my visit short, and observe the fast without making a production of it. If absolutely necessary, I have a brief quiet word with the host ahead of time and offer to bring a fasting dish that everyone can share (thus not broadcasting it). I also do not decorate or put up a tree until Christmas Even or the day before if I am going to be away (very rare). The same goes for other decorations and Christmas music. If there are Christmas programmes on telly, I set my DVR to record and watch them over Christmas week. Again, this is my personal observance, as for what other Orthodox should do, YMMV.
This year will be different as I am in the process of moving in with relatives due to unfortunate circumstances. As these relatives are non-Orthodox and very into Christmas, I will have little say iin regard to music or decorations outside my personal bedroom. In there however, I will maintain my own tradition. Maybe if I am so blessed, I can convince them to keep their tree and decorations up through Orthodox Christmas.
On a personal note, I much prefer the German/Austrian custom of the Christ Child bringing the gifts Christmas Even, than the secular version of Saint Nicholas... Santa Claus. I also like the German/Austrian tradition surrounding St Nicholas and Krampus.