I bought those long, wide, red, velvety ribbons/swags a few years ago. I tack them to the wall around an arch in our living room where we usually put the Christmas tree. Then, I staple the cards to the ribbon and let them drape down. The cards and staples come out easily after the season so I can re-use the ribbon next year.

One year when I was especially broke and had no ornaments for the sad, little Charlie Brown Christmas tree I had, I punched a hole in the corner of the cards and hung them on the tree as my ornaments.