Effective email is essential during the holidays. Here's a summary of a great article by Jason Gervias:

1. Clearly & quickly state the benefit.  You can’t be too concise because people scan email.
2. Always segment your list, e.g. by geography, purchase behavior, or industry.
3. Stick to a single call to action.
4. Frequency: biweekly messages are the most the majority of contacts will tolerate.
5. Start with a great subject line, e.g. ask a question, offer value, create urgency.

Based on the above criteria, Moosejaw (again) gets this one right:

Source: Uploaded by user via Meghan on Pinterest