If they're into artsy games, games with customization, games with nice-looking female characters, or just shamelessly feminine games, then may I suggest... Style Savvy?
(Depending on what region your friend is in, the game may be called Style Savvy, Style Boutique, Girls Mode, or Girls Style.)
It's a great and cute fashion game where you work at fashion boutique store, and help out customers pick out a specific fashion item or whole outfit, as well as entering fashion contests.
There are various styles to choose from, and both your avatar and customers can wear them too!
The game supports local multiplayer for competing in fashion contests and visiting the other person's fashion boutique.
Wi-Fi is also supported for downloading fashion items online.