CrewCuts from J.Crew is one of my personal favorites, and they have some fantastic accessories for your little hipsters, such as these great hair accessories to keep her hair tidy but oh so fashionable:
Girls’ flower headband:
Girls’ carnation headband: 
Girls’ silk flower hair clip:
And while it’s not very useful for the hair, I thought this backpack was fantastic. Girls’ petal drawstring backpack:
