Parents generally love dressing their kids up so that they look cute, so when you’re advertising kids clothes fro younger kids, the customer is usually the parent. Here are a picture from http://blogs.babble.com that I think are great and would sell a heap of parents on the outfits.
The girls in the pictures look about 6 or 7 years old. So the promotion might be effective with them too as long as their friends like them too and/or there are similar outfits in TV shows or movies they like ( you’d probably need to check these things before finalizing any display ). There’s more info about promoting kids clothes on our page about child mannequins.