Rachel's Hat

I knit this hat with a kind of diamond pattern on size 2 needles for my sister, Rachel for Christmas. I think it's a bit large for her though. I need to measure the size of all my sisters heads. I find it's hard to measure someone's head without giving away my plans to knit them a hat. Drawing an outline of their hands would be good for gloves and mittens also. Ring sizes would be good too.