I used Lion Brand jiffy in black ( hard to see the stitches ) it turned out really nice I added graduated borders of multi colored eyelash yarn. In other words like ten rows black than 4 rows color 4 rows black 6 rows color 4 rows black 4 rows color than whatever length I felt it needed and repeated the border. I added fringe out of both yarns mixed. I was very pleased with the way it turned out. It was perfect for the young woman it was intended for and she uses it daily.
I think you can pick whatever color you want or if you know the recipient try and keep their color like in mind, otherrwise the choice of yarn and color is up to the individual maker which in my opinion makes it one of those trulu GREAT projects