Whether it was chains and pins at Alexander McQueen, jewelled headbands at Dolce & Gabbana, or flowers at Rodarte, there are two factors that keep hair accessories grown-up:
1. Texture: as in, the hair has some.
2. Placement: is haphazard (like, before rushing out the door the model stuck granny's brooch in her hair).
If you're keen to try a headband (and want to avoid looking like a long-lost cast member from a '90s daytime soap opera), don't place the headband on your head and then push it forward again (which results in a little bump between the hairline and the band.) Simple.
After more inspiration? See these celebrities:
Diane Kruger's ornate pin makes a nice contrast with her casually pulled back hair; Emma Stone slipped a silver slide into her choppy lob at the Golden Globes; and then there's the eternally chic Brigitte Bardot, whose wispy hairline is tres chic.