So you have a 10U player, just telling her works? Most parents can't follow some of these posts let alone a young kid.
Telling her what works?
Did you read what I wrote? IMO, many kids are born with some of the natural movements seen in a good swing. Kids that are born with a natural hip cock, often times have a natural hand cock. Many of us coaches in our brilliance, mess up the kid's sequence by removing the hand cock. I don't know any instructors or coaches who understand the role the hand cock plays in the sequence. I don't recall anyone even discussing the subject on the various message boards until I started raising the issue last year.
Last year while studying the Hodge overhand throw material that I own; it suddenly clicked what the hand cock in hitting really was. I then began experimenting with the overhand throw hand break in various hitting handset styles used by hitters. This experimentation, further helped me understand what hitters with very different styles did with their hands when they cocked the hips.
With this new found knowledge, I don't mess up a 10yo's sequence like a lot of closed minded coaches and instructors do. If I'm working with a 10yo that has a natural hip cock, and they drop their hands during their hip cock, I tell them not to let anyone coach that out of them. I'm not going to get them doing tee drills or Matrix drills in an attempt to prevent them from dropping their hands.
If a 10yo old doesn't have a natural hip or hand cock, then IMO a good place to start is teaching them how to throw overhand correctly.