I like the magazine subscription idea. I was also going to say a gift card to Claire's or something like that. I think B&BW gift card is good too. So, ditto Alicia, LOL.
Cecile loves books. Diary of a wimpy kid stuff especially popular and there are also lots of knock off diary style books too. Music. Craft stuff. Friendship bracelets esp. Making them herself. Journals, diaries and cool pens to write with. jewellery and scarves and fun socks to wear with her converse.
Personally, I hate claires though Cecile loves it. I think american eagle has some real cool jewelry - a bit more pricey then claires but way cooler and they almost always are on sale.
Also, if you go to the back of any abercrombie store, they always have tons of t-shirts on sale for like 9-12 bucks each. That is always super cool.