The holiday season is usually the strongest in eCommerce and you get extraordinary numbers of new customers. That's a great opportunity and you should be fighting to keep those customers as regulars.
The really nice thing about holiday shoppers is that they usually shop for gifts and therefore your products are given to other people. This opens the door to not one, but two potential customers at a time.
What can you do to re-engage holiday buyers after the holidays?
send them product- and usage-related content via email (they will share it with the recipient of the gift to improve their experience)
ask for feedback (same logic - the gift giver will forward it to the receiver; you can include an email field to collect the receiver's address)
offer complimentary products
based on the products bought, offer new season items when the time comes
judging by the items purchased, send holiday offers on other occasions - Mother's Day, Father's Day, Valentine's Day, etc.
How to do that using Metrilo?
From the main menu, go to Revenue Breakdown.
From the time period dropdown menu (top right corner), select the period you believe to have brought the most holiday shoppers, e. g. 15th Nov - 15th Dec. (While there are people who start Christmas shopping in August, choose a shorter period for more accurate results.)
In the breakdown by new and returning customer below, click the number of new customers to get the full list.
Apply a global "Holiday shopper" tag to the whole list (the Tag button is at the top).
Go to the Customer Database tab and filter customers by that tag.
Then, add a filter by the number of orders equal to 1. Those would be your one-time holiday shoppers.
Now, send them an email to invite them back to your store.
Note: If you have a special holiday product category that you know will give you all holiday shoppers, then you can simply filter the people who shopped it and be done:
In Customer Database, use the filter by Product categories they interacted with - choose your holiday category and "ordered" to be sure they shopped that category.