Pants of your choice
Ribbon, fabric strip, lace, etc of your choice
I was really tempted to use a tribal print trim (they made the tuxedo pants look more like mariachi pants) or a wide turquoise sheer ribbon, but really liked the subtle elegance of the white and gold pattern so went with it instead.
What you do:
Sew (or use strong glue to attach) the ribbon down the side seam of your pants. Done and done!
I love how the white on white makes it actually look like a classic tuxedo pant! Though I'm still really tempted to make another pair with white and turquoise.