Here are some things to consider with your Online Store for Christmas.  

Are you offering Christmas specials? 

You can put up special Christmas only products that have special pre-Christmas offers.  Gift buyers come in many different types and good quality novelty items sell well at Christmas.

Add Christmas Keywords  
Make sure that you add the Christmas keywords to your meta-keywords with plenty of time to get crawled by the search engines before Christmas. Also make sure that you add Christmas Gift category names and description text to match up with your keywords.  But remember timing is important.  How often does Google crawl your website homepage?  For most online shops it might be every 5-10 days so to get your changed messages out there -  it is not instantly available.  Now might be a good time to set up some web analytics.

Christmas is the peak retail period of the year and preparation should have already started.  If it hasn't - START NOW!
There are two guarantees:  Christmas will happen and people will still spend up on gifts and food for the holiday season.

Let's start by looking at your online store:
You have issues to cover but the key issue is time.  The date for Christmas doesn't change so by December 24th your Christmas business is done. So plan backwards:

• How long does it take you to pick, pack and ship?  That will determine the last date for selling online and delivering by Christmas.  Remember, there may be backlogs in delivery so check with your shipping company.
• What are the peak number of orders that you can handle each day and still get the deliveries out?
• How much stock will you need on hand?
• What content changes do you need for your online shop?
• Do you have photos and new stock information from suppliers?
• What about pre-Christmas promotions and sales?
• What about Christmas gifts and gift wrapping materials?