Some form of texturizing is always best when dealing with thin strands. Here Kate has big, loose ringlets draped around her shoulders. The top has been stylishly pulled back having first been captured into some lift in the front before pinning down. Backbrushing could be done here to ensure hair will stay in position.
There are a lot of women running around with fine hair. Kate Bosworth certainly has a thin head of hair yet it does not stop her from looking beautiful.