I'm a hairtstylist, so I have experience with this type of hair.
One thing you need to do, is get a really good moisturizer, like Sebastion's potion 9, and use that after you wash your and her hair.
Also, shampoo only every two, maybe three days depending on how oily or dirty her hair gets. If her scalp gets dirty but her hair is fine, you can run a cotton ball of witchhazel through her scalp, careful to avoid too much of her hair. People with wild, curly hair need to wash less b/c their hair has less moisture do to the scalp oil traveling down to moisturize the ends of the hair.
Also, after you and her wash your hair, towel dry it very gently, ring the water out carefully, then gently massage the hair with the towel, almost like milking a cow in an up and down motion.
Use a very wide tooth comb, a pick or your fingers to get out tangles, just be careful not to overcomb, otherwise it will separate the curl pattern and contribute to the messy look. This is the time you can part the hair, a deep side part will look very pretty.
Once you do that, add in your potion 9 or moisturizer and maybe even a mouse or styling cream for curly hair. Using your fingers, work the curls into place and very lightly scrunch just a little.
If you want to blow dry, use the tooth diffuser attachment, place the curl on there and dry while pushing the blow dryer up towards your scalp. But I don't recommend using the dryer until your hair is at least 60% air dry anyways.
After that, your/her hair should have a more uniform curl and less crazy looking. You can use a light serum to add in shine if you want, or leave it alone and use a gentle working spray to hold in place. Just remember, don't overdo the product if you are going to be washing every few days.
I would recommend you cut the hair though, it's true that growing hair long helps to weigh down the curls, but dry and uneven ends will make them worse and less manageable. I would do a light trim every 6 weeks or so, and have some gentle layers added in, not only will it make your curls more beautiful, but it will be easier to style. A good stylist will cut the hair to define the curls, so ask around for someone who is good with curly hair. And NEVER let anyone use a razor on curls.
For your daughter, I would maybe even recommend doing a little braid instead of a ponytail for her, or really help teach her how to do a low ponytail, much easier for girls to do. Also, little girls with wild hair are adorable! I would play it up.
The 'messy' tousled partially curled hair can be really attractive, lots of people try and get this style. If you just do a few simple tweaks, you can get that look too:
http://hair.lovetoknow.com/Wavy_Hair_Styles_Ideas