I just love using gold, silver or copper mirror paper on my handmade cards - as layer borders or die cut accents. The wine themed card below were a perfect match to gold mirror paper. The accents a somewhat subtle but you really get a bang for your buck.
The cheers sentiment was cut twice in gold mirror paper and it really pops off the card front. And it looks great with the gold cording.
This paper is very easy to work with and it die cuts beautifully. I hope you add mirror paper to your next project.