This is completely how my bestfriends dressed when we were growing up (non abaya version 'course). Shout out Amanda and Brittany, and Leigh-Anne and crew, and Carlie, LOL. It's a Westcoast thaaaang.
Abaya from http://www.muslimbase.com/product_info.php?products_id=4686 for $31.99 GBP
Square hijab in a california gingham http://www.forever21.com/product.asp?catalog_name=FOREVER21&category_name=acc&product_id=1056011939&Page=4 for $8.80 USD.
This set was hard for me to create actually, because I have never worn this look (I have a European style but with a relaxed African vibe and for I am picking up some Arab glamour here on in to my later years LOL), even though the casual girlie flirty style was TOTALLY the rage of my highschool, before the ooompha looompha tramp of my little sister's generation took over in thongs (oooompha looompha is a reference to "Charlie and the Chocolate Factory" characters that had orange skin and green hair and that's exactly how the Ooompha Loooompha tramps in my highschool looked with their fake tanner orange skin and green-blonde high-lighted hair:D). Anyways, surfer shorts and cool tees with a pretty grown up Marc Jacobs bag and thongs (the sandal kind) or little girlish flats is all the thing. Layer a long beaded necklace under the hijab, and do it in Gingham, like Gidget. (Gidget was a movie surfer, for those who might not get the reference).