Forum Moderators: not2easy
With regards to the desing, maybe typical Christmas colours (what I regard to be red and green), maybe some holly and snow or something? Also, you could place some ads with pictures of presents and so on and a reminder that Christmas is nearing. You could maybe also link these to a special offer for Christmas.
I'm neither a designer, nor an expert in e-commerce, so these are from a customer's perspective.
Hope this helps,
Cheers
Richard
Further if your returning users are used to a general feeling
applying overall changes can be detrimental
unless using changes to announce a discount!
then they don't care :)
so maybe you may give it a X-mas feeling, annonce some specials and trigger more sales.