Have an array of nail polish colors set out to choose from and pick one for your nails. Let your friend paint your nails and you can paint hers. Get out the hair supplies, straightener, curling iron, and hairspray and create a fun hairstyle for your friend. You can go crazy and wild, or fun and cute. Try out different hair styles with each other and take tons of pictures. Either make your own facial mask or buy one at the store and give each other relaxing facials. Don't forget the cucumbers for the eyes!

TL;DR in Chinese:
给对方涂指甲。 给对方做头发。 给对方美美容。