Equation:
Little girls often like Dora the Explorer (at least nowadays).
+
Little girls often like princesses.
+
Little girls often like to dress up.
=
A Dora the Explorer's Snow Princess dress.
I used old white t shirts and some blue stretchy fabric.
It's not perfect, as I didn't have any measurements, nor a live model around. So the bodice turned out rather big, but that has it's benefits with dressing up, and it means she can still wear it when she grows bigger.