Turn off the TV! :^) Seriously, shows like that can be obsessive.
Your little girl is old enough for you to tell her that she has THIS much space and no more. Keep enough bins to be practical but don't overdo it at all. Tell her that her things have to live in the bins. She can't have any overflow. If she adds things to her bins, she must take things out as well. It's all right to keep some things and let other things go! (The other things won't mind!)
When it comes to clothes and toys, when the charity truck is in the neighborhood and you're filling up a box, ask her to put some things in it, too. Explain to her that there are other children who can only get toys and clothes this way.
Give her an inexpensive "magnetic page" scrapbook and tell her that she can put her pieces of torn paper with lines drawn upon them in the book, but once it's filled, whatever she wants to add to the book must be at the cost of something else going out. Let her know that smart people always learn to make choices like this.
Of course you need to set her a good example by going through your closets and cupboards and making sure you're not hoarding anything. You might even let her help you. That means that if she thinks that pair of pink shoes is ugly, you let them go, so be prepared!
I am a pack rat (that's what I call it!), come from a long line of pack rats, and have children who were pack rats! I used to have to deal with their clutter, and as teenagers when they would go off to camp for a week they knew Mama would be cleaning out their rooms! I'd put notes from school friends in a shoebox, for example, but gum wrappers were not allowed to remain, even if they were considered treasures.
I have to keep watch over myself, too. There's a charity truck in the neighborhood next week.