Because I collect several kinds of dolls, I have a lot of doll clothes. Most of my American Girl clothes are stored in a bin, but my A Life of Faith dolls have lots of fluffy dresses that can't be put into boxes. For years I've been hanging them in my closet on the built-in rack, but it's not very large and I needed more space for my own clothes. My mother was starting to go crazy over it, so she came up with a great idea for vastly improving my storage situation without crushing the dresses.
Isn't my mother brilliant? Isn't she?
What we have here is a second closet rack above the first one, low enough so that you can still reach the clothes without lugging out the step ladder, but high enough so that the dresses won't trail the level below. This gets them out of the regular closet space and gives them a section all their own. As a bonus, on the top I can fit empty AG boxes.
We bought the extra closet rack at Lowes. This one was about four feet, and it is attached at the end of the closet. If that's all the storage you need, you can stop there. If not, you can buy more pieces and even extend it to the length of your previous rack. Some walk-in closets would probably be a better candidate for this since you can usually see the end of the closet wall much better, but it certainly worked for mine which just has sliding doors.
So, if you're having trouble with doll clothing storage, I hope this helps you! Ask your dad for help if, like me, you're more handy with dolls than drills.
P.S. You could also use this idea for pet clothes.