Holidays are a great opportunity to enrich your manuscript. The trick is to not gloss over the holliday, but to add vivid descriptions as to how the holiday is celebrated by your characters.
You can draw on this by your own experience. Think of a holiday, such as Thanksgiving. What's the weather like outside? That will depend on where you live and/or the climate vagaries of the fictional year you create. Such descriptions can add greatly to the setting of your story.
Who is invited to your character's house to celebrate the holiday? Is someone missing? Why? A rift in the family, illness, death? Who prepares the meal? The mother, the wife, the son, the daughter, one, some, or all? Who helps? Children, spouse, friend? How is the table set? Disposable plates, glasses, silverware or fine china and silver? Such details are a good way to show the station in life of your characters, whether they're well-off, just-married, college students, maybe, or members of a large family.
What's on the menu? Does it reflect a character's ethnicity, a quirk, or maybe an effort to please someone who's held dear or who's domineering? Many people eat turkey for Thanksgiving, but maybe your character is alone and eating spam. Why?
What about guilt? There are lots of possibilities for that, such as a dinner guest who forgot to bring a hostess gift. Then there's the working wife or mother or single who feels bad because she uses canned gravy and ready-made dressing instead of making them from scratch. Why does she work? Is it because she needs the money, wants to get away from home for a while, or has a high profile position? I'm using the female gender here, because it's the women who usually cook the holiday meals, but there are exceptions. If so, that's another good difference to emphasize in your book.
Or what about the eternal ying and yang of invitations to the husband's and wife's houses on the same day, at the same time? Where to go? Who to please? That's a tough one.
What other holiday descriptions can you think of, either from your own novel or someone else's?