With the holiday season wrapping up, have you contacted your best customers with a non-marketing email yet?
Something that thanks them for being a customer, offers them something entertaining (e.g. joke or story), or something other than a direct call to buy from you.
Even though everyone is flooded with promotional messages right now, a gratitude email like that would cut through the noise. It won't lead directly to sales (but might). It would lead to a better relationship with the customer going into the new year though.
With your best customers, that could be worth more than a handful of additional sales.
If you're not sure who your best customers are, start with the ones who order frequently. In RFM that would be the Frequency 5 group and in Repeat Customer Insights I'd recommend the Loyal and VIP groups.
If you need inspiration about what to say, look at what some greeting cards use for copy. Both Thank You and joke cards should give you a lot of inspiration.