How old is your DD? If she's really little, you might want to cut it a bit shorter to make it easier to take care of. If she's old enough to shower, this routine might work:
I had hair like that, very fine, with just HORRIBLE tangles, especially on the nape of my neck. What finally fixed it was always washing it in the shower, with a LOT of thick conditioner (nothing that has a lot of alcohol that will dry it), and doing the comb-out *in* the shower, with the water running, with a really fat comb. Also, always starting to comb from the bottom up; going from the top down just makes the tangles worse. After toweling it gently (no tousling with the towel), spray on leave-in conditioner/detangler (I use Infusium), comb it out again, and if she has to sleep on it, braid it.