Consider your audience and purpose, and write accordingly.
Be sensitive when choosing your words—keep in mind that the person you are addressing might not celebrate the holiday(s) that you mention.
Send your letters early, especially for the end-of-year holidays or winter season because of the increased volume in the mail.
When possible, send a personalized letter—such an effort will be much more appreciated than simply receiving a “group letter.” If you do choose to send a group letter, try to add a personalized note at the bottom.
Close by wishing the person well and expressing your hope that he/she enjoys the holiday. End on a positive note.
Review your letter before sending it and revise if necessary. Keep your letter interesting and upbeat—and if possible, to one page.
Ask family members and others before sharing personal or important information about them. For members of your own family (e.g., spouse and older children), it is best to let them read the letter before sending it.
How to write a holiday letter in conjunction with a sale or other special promotion:
Extend a warm greeting.
Acknowledge the upcoming holiday.
Describe the offer or special sale that you are having, including any special discounts or other incentives.
If appropriate, express your appreciation for the customer and for his/her business over the years (or months, etc.).
Close by reiterating warm wishes for the holiday.
How to write a holiday letter to employees or business colleagues:
Begin your letter with a warm, personal greeting.
Mention the holiday or season for which you are sending the letter.
If appropriate, thank the person for his/her hard work and dedication to your company or organization.
If you are including with your letter a bonus check or gift of some kind, indicate as much in your letter.
If you are also announcing a party or other social event in your letter, be sure to include important information, such as the date, time, location, appropriate attire, and whether or not the person needs to RSVP, how, and by when.
Include any message you want to about the successes or accomplishments of that year (or quarter, etc.), or the goals for next year. For personalized letters, mention specific accomplishments of the various employees or coworkers or colleagues.
Close your letter by expressing your wish that the person have a happy holiday (and a prosperous new year, if this is an end-of-year letter).
How to write a personal holiday letter:
Open with a warm greeting, acknowledging the occasion.
Include an update on your life or that of your family—mention latest events or changes, happy news, accomplishments, noteworthy goals, humorous events, etc.
Make polite inquiries about the life of the reader.
If you have included a gift or money, briefly mention this fact.
You might also include such things as: warm memories, an invitation to spend time with the reader, or reminders about important dates, such as upcoming get-togethers or family reunions, graduations, marriages, and the like.
Include a current picture of your family or other keepsake, if desired.
Include your current contact information, such as e-mail, cell phone or home number, etc., in case the reader does not have it or has lost track of it.
In closing, express your wishes for a pleasant holiday.