Shining Stars - simple tape design tree, with star garland. Washi tape would work well for this, as it wouldn't mar the wall paint. I just picked up some wide white washi tape, with "Merry Christmas" printed on it.
Use card stock and misc buttons to make your own Christmas cards. The card stock can be bought at Walmart, etc. or at most any craft store. The buttons come in bags at most craft, hobby, or fabric stores.