I agree with snowolf, it's mostly about upper body rotation at that age, any analogy/game you can do that gets her to point her shoulder/front arm will work, just make sure she is comfortable sliding on her toe edge first before you try and make any turns. Most 7 year olds I have taught hate being in their toes because they can't see down the hill.
I will add that the right equipment makes a massive difference at that age. The stuff burton is coming out with right now is amazing. Reverse Camber with a beveled base does wonders for the little ones. Going a little bit shorter can help also.
She's confident on her heel edge but I haven't seen her stay on her toe edge more than a couple of seconds. She's not physically timid and it looks like she's comfortable trying to go onto her toe but she seems to wipe out nearly every time.
I bought her a kids' Rossignol with reverse camber. It looks very similar to Burton's V-Rocker shape but I don't know about the beveling. Her big sister has a Burton with V-Rocker and she took to snowboarding pretty quickly.