I'm terrible with the holidays! I kind of go out of control with the "holidays don't count" mentality. Instead of thinking long-term, I think more of "One Day at a Time".
During the wintertime I also just naturally crave hot, hearty and decadent food. I've been taking small steps, substituting those types of foods for healthier ones, but still taste amazing. (instead of heavy pork chili with the fixins, I made jalepeno sweet potato and chicken chili with pita chips!) If you have a sweet tooth craving, don't deny it, snack sensibly! If fruit isn't cutting it for you, I love mini York Peppermint Patties at just 50 cals. They're easier to stop at "just one" because the chocolate and peppermint seem to sit on your tastebuds a lot longer than other mini chocolate bars.
Good luck, and don't beat yourself up if you slip up one day, just start anew the next!